diff --git a/fastNLP/api/model_zoo.py b/fastNLP/api/model_zoo.py
index 9069ae55..a54a53d9 100644
--- a/fastNLP/api/model_zoo.py
+++ b/fastNLP/api/model_zoo.py
@@ -1,5 +1,3 @@
-import torch
-
 import hashlib
 import os
 import re
@@ -7,6 +5,8 @@ import shutil
 import sys
 import tempfile
 
+import torch
+
 try:
     from requests.utils import urlparse
     from requests import get as urlopen
@@ -132,7 +132,3 @@ if tqdm is None:
 
             sys.stderr.write('\n')
 
-
-if __name__ == '__main__':
-    pipeline = load_url('http://10.141.208.102:5000/file/download/infer_context-4e86fd93.pkl', model_dir='.')
-    print(type(pipeline))
diff --git a/fastNLP/api/processor.py b/fastNLP/api/processor.py
index 711f2b67..d6a68412 100644
--- a/fastNLP/api/processor.py
+++ b/fastNLP/api/processor.py
@@ -1,14 +1,15 @@
-import torch
-from collections import defaultdict
 import re
+from collections import defaultdict
+
+import torch
 
-from fastNLP.core.dataset import DataSet
-from fastNLP.core.vocabulary import Vocabulary
 from fastNLP.core.batch import Batch
+from fastNLP.core.dataset import DataSet
 from fastNLP.core.sampler import SequentialSampler
+from fastNLP.core.vocabulary import Vocabulary
 
 
-class Processor:
+class Processor(object):
     def __init__(self, field_name, new_added_field_name):
         self.field_name = field_name
         if new_added_field_name is None:
@@ -17,7 +18,7 @@ class Processor:
             self.new_added_field_name = new_added_field_name
 
     def process(self, *args, **kwargs):
-        pass
+        raise NotImplementedError
 
     def __call__(self, *args, **kwargs):
         return self.process(*args, **kwargs)
@@ -132,13 +133,14 @@ class Num2TagProcessor(Processor):
 
 
 class IndexerProcessor(Processor):
-    def __init__(self, vocab, field_name, new_added_field_name, delete_old_field=False):
+    def __init__(self, vocab, field_name, new_added_field_name, delete_old_field=False, is_input=True):
 
         assert isinstance(vocab, Vocabulary), "Only Vocabulary class is allowed, not {}.".format(type(vocab))
 
         super(IndexerProcessor, self).__init__(field_name, new_added_field_name)
         self.vocab = vocab
         self.delete_old_field = delete_old_field
+        self.is_input = is_input
 
     def set_vocab(self, vocab):
         assert isinstance(vocab, Vocabulary), "Only Vocabulary class is allowed, not {}.".format(type(vocab))
@@ -146,13 +148,14 @@ class IndexerProcessor(Processor):
         self.vocab = vocab
 
     def process(self, dataset):
-        assert isinstance(dataset, DataSet), "Only Dataset class is allowed, not {}.".format(type(dataset))
+        assert isinstance(dataset, DataSet), "Only DataSet class is allowed, not {}.".format(type(dataset))
         for ins in dataset:
             tokens = ins[self.field_name]
             index = [self.vocab.to_index(token) for token in tokens]
             ins[self.new_added_field_name] = index
 
-        dataset._set_need_tensor(**{self.new_added_field_name: True})
+        if self.is_input:
+            dataset.set_input(self.new_added_field_name)
 
         if self.delete_old_field:
             dataset.delete_field(self.field_name)
@@ -161,6 +164,9 @@ class IndexerProcessor(Processor):
 
 
 class VocabProcessor(Processor):
+    """Build vocabulary with a field in the data set.
+
+    """
     def __init__(self, field_name):
         super(VocabProcessor, self).__init__(field_name, None)
         self.vocab = Vocabulary()
@@ -178,17 +184,20 @@ class VocabProcessor(Processor):
 
 
 class SeqLenProcessor(Processor):
-    def __init__(self, field_name, new_added_field_name='seq_lens'):
+    def __init__(self, field_name, new_added_field_name='seq_lens', is_input=True):
         super(SeqLenProcessor, self).__init__(field_name, new_added_field_name)
+        self.is_input = is_input
 
     def process(self, dataset):
         assert isinstance(dataset, DataSet), "Only Dataset class is allowed, not {}.".format(type(dataset))
         for ins in dataset:
             length = len(ins[self.field_name])
             ins[self.new_added_field_name] = length
-        dataset._set_need_tensor(**{self.new_added_field_name: True})
+        if self.is_input:
+            dataset.set_input(self.new_added_field_name)
         return dataset
 
+
 class ModelProcessor(Processor):
     def __init__(self, model, seq_len_field_name='seq_lens', batch_size=32):
         """
@@ -238,6 +247,7 @@ class ModelProcessor(Processor):
         device = torch.device(device)
         self.model.to(device)
 
+
 class Index2WordProcessor(Processor):
     def __init__(self, vocab, field_name, new_added_field_name):
         super(Index2WordProcessor, self).__init__(field_name, new_added_field_name)
@@ -251,6 +261,7 @@ class Index2WordProcessor(Processor):
 
 
 class SetTensorProcessor(Processor):
+    # TODO: remove it. It is strange.
     def __init__(self, field_dict, default=False):
         super(SetTensorProcessor, self).__init__(None, None)
         self.field_dict = field_dict
@@ -264,6 +275,7 @@ class SetTensorProcessor(Processor):
 
 
 class SetIsTargetProcessor(Processor):
+    # TODO; remove it.
     def __init__(self, field_dict, default=False):
         super(SetIsTargetProcessor, self).__init__(None, None)
         self.field_dict = field_dict
diff --git a/fastNLP/core/__init__.py b/fastNLP/core/__init__.py
index b16fe165..b62d5624 100644
--- a/fastNLP/core/__init__.py
+++ b/fastNLP/core/__init__.py
@@ -2,7 +2,7 @@ from .batch import Batch
 from .dataset import DataSet
 from .fieldarray import FieldArray
 from .instance import Instance
-from .losses import Loss
+from .losses import LossFromTorch
 from .optimizer import Optimizer
 from .sampler import SequentialSampler, BucketSampler, RandomSampler, BaseSampler
 from .tester import Tester
diff --git a/fastNLP/core/dataset.py b/fastNLP/core/dataset.py
index 57171e25..f4963d0a 100644
--- a/fastNLP/core/dataset.py
+++ b/fastNLP/core/dataset.py
@@ -9,32 +9,20 @@ from fastNLP.core.utils import get_func_signature
 _READERS = {}
 
 
-def construct_dataset(sentences):
-    """Construct a data set from a list of sentences.
-
-    :param sentences: list of list of str
-    :return dataset: a DataSet object
-    """
-    dataset = DataSet()
-    for sentence in sentences:
-        instance = Instance()
-        instance['raw_sentence'] = sentence
-        dataset.append(instance)
-    return dataset
-
-
 class DataSet(object):
     """DataSet is the collection of examples.
     DataSet provides instance-level interface. You can append and access an instance of the DataSet.
     However, it stores data in a different way: Field-first, Instance-second.
 
     """
+
     def __init__(self, data=None):
         """
 
-        :param data: a dict or a list. If it is a dict, the key is the name of a field and the value is the field.
-                All values must be of the same length.
-                If it is a list, it must be a list of Instance objects.
+        :param data: a dict or a list.
+                If `data` is a dict, the key is the name of a FieldArray and the value is the FieldArray. All values
+                must be of the same length.
+                If `data` is a list, it must be a list of Instance objects.
         """
         self.field_arrays = {}
         if data is not None:
@@ -60,6 +48,7 @@ class DataSet(object):
         def iter_func():
             for idx in range(len(self)):
                 yield self[idx]
+
         return iter_func()
 
     def _inner_iter(self):
@@ -69,7 +58,8 @@ class DataSet(object):
                 self.idx = idx
 
             def __getitem__(self, item):
-                assert item in self.dataset.field_arrays, "no such field:{} in Instance {}".format(item, self.dataset[self.idx])
+                assert item in self.dataset.field_arrays, "no such field:{} in Instance {}".format(item, self.dataset[
+                    self.idx])
                 assert self.idx < len(self.dataset.field_arrays[item]), "index:{} out of range".format(self.idx)
                 return self.dataset.field_arrays[item][self.idx]
 
@@ -79,6 +69,7 @@ class DataSet(object):
         def inner_iter_func():
             for idx in range(len(self)):
                 yield Iter_ptr(self, idx)
+
         return inner_iter_func()
 
     def __getitem__(self, idx):
@@ -217,9 +208,17 @@ class DataSet(object):
                 raise KeyError("{} is not a valid field name.".format(name))
 
     def get_input_name(self):
+        """Get all field names with `is_input` as True.
+
+        :return list field_names: a list of str
+        """
         return [name for name, field in self.field_arrays.items() if field.is_input]
 
     def get_target_name(self):
+        """Get all field names with `is_target` as True.
+
+        :return list field_names: a list of str
+        """
         return [name for name, field in self.field_arrays.items() if field.is_target]
 
     @classmethod
@@ -243,7 +242,7 @@ class DataSet(object):
         :return results: if new_field_name is not passed, returned values of the function over all instances.
         """
         results = [func(ins) for ins in self._inner_iter()]
-        if len(list(filter(lambda x: x is not None, results)))==0: # all None
+        if len(list(filter(lambda x: x is not None, results))) == 0:  # all None
             raise ValueError("{} always return None.".format(get_func_signature(func=func)))
 
         extra_param = {}
@@ -269,6 +268,12 @@ class DataSet(object):
             return results
 
     def drop(self, func):
+        """Drop instances if a condition holds.
+
+        :param func: a function that takes an Instance object as input, and returns bool.
+            The instance will be dropped if the function returns True.
+
+        """
         results = [ins for ins in self._inner_iter() if not func(ins)]
         for name, old_field in self.field_arrays.items():
             self.field_arrays[name].content = [ins[name] for ins in results]
@@ -338,10 +343,33 @@ class DataSet(object):
         return cls(_dict)
 
     def save(self, path):
+        """Save the DataSet object as pickle.
+
+        :param str path: the path to the pickle
+        """
         with open(path, 'wb') as f:
             pickle.dump(self, f)
 
     @staticmethod
     def load(path):
+        """Load a DataSet object from pickle.
+
+        :param str path: the path to the pickle
+        :return DataSet data_set:
+        """
         with open(path, 'rb') as f:
             return pickle.load(f)
+
+
+def construct_dataset(sentences):
+    """Construct a data set from a list of sentences.
+
+    :param sentences: list of list of str
+    :return dataset: a DataSet object
+    """
+    dataset = DataSet()
+    for sentence in sentences:
+        instance = Instance()
+        instance['raw_sentence'] = sentence
+        dataset.append(instance)
+    return dataset
diff --git a/fastNLP/core/losses.py b/fastNLP/core/losses.py
index fbd64e81..ed935c9d 100644
--- a/fastNLP/core/losses.py
+++ b/fastNLP/core/losses.py
@@ -7,14 +7,13 @@ import torch.nn.functional as F
 from fastNLP.core.utils import CheckError
 from fastNLP.core.utils import CheckRes
 from fastNLP.core.utils import _build_args
-from fastNLP.core.utils import _check_function_or_method
 from fastNLP.core.utils import _check_arg_dict_list
+from fastNLP.core.utils import _check_function_or_method
 from fastNLP.core.utils import get_func_signature
 
 
 class LossBase(object):
     def __init__(self):
-        # key: name in target function; value: name in output function
         self.param_map = {}
         self._checked = False
 
@@ -159,8 +158,18 @@ class LossBase(object):
 
         return loss
 
+
 class LossFunc(LossBase):
+    """A wrapper of user-provided loss function.
+
+    """
     def __init__(self, func, key_map=None, **kwargs):
+        """
+
+        :param func: a callable object, such as a function.
+        :param dict key_map:
+        :param kwargs:
+        """
         super(LossFunc, self).__init__()
         _check_function_or_method(func)
         if key_map is not None:
@@ -254,19 +263,19 @@ def _prepare_losser(losser):
 
 
 def squash(predict, truth, **kwargs):
-    '''To reshape tensors in order to fit Loss functions in pytorch
+    """To reshape tensors in order to fit loss functions in pytorch
 
     :param predict	: Tensor, model output
     :param truth	: Tensor, truth from dataset
     :param **kwargs : extra arguments
 
     :return predict , truth: predict & truth after processing
-    '''
+    """
     return predict.view(-1, predict.size()[-1]), truth.view(-1, )
 
 
 def unpad(predict, truth, **kwargs):
-    '''To process padded sequence output to get true loss
+    """To process padded sequence output to get true loss
     Using pack_padded_sequence() method
     This method contains squash()
 
@@ -277,7 +286,7 @@ def unpad(predict, truth, **kwargs):
                       the i-th element is true lengths of i-th sequence
 
     :return predict , truth: predict & truth after processing
-    '''
+    """
     if kwargs.get("lens") is None:
         return predict, truth
     lens = torch.LongTensor(kwargs["lens"])
@@ -288,7 +297,7 @@ def unpad(predict, truth, **kwargs):
 
 
 def unpad_mask(predict, truth, **kwargs):
-    '''To process padded sequence output to get true loss
+    """To process padded sequence output to get true loss
     Using mask() method
     This method contains squash()
 
@@ -299,7 +308,7 @@ def unpad_mask(predict, truth, **kwargs):
                       the i-th element is true lengths of i-th sequence
 
     :return predict , truth: predict & truth after processing
-    '''
+    """
     if kwargs.get("lens") is None:
         return predict, truth
     mas = make_mask(kwargs["lens"], truth.size()[1])
@@ -307,7 +316,7 @@ def unpad_mask(predict, truth, **kwargs):
 
 
 def mask(predict, truth, **kwargs):
-    '''To select specific elements from Tensor
+    """To select specific elements from Tensor
     This method contains squash()
 
     :param predict	: Tensor, [batch_size , max_len , tag_size]
@@ -317,7 +326,7 @@ def mask(predict, truth, **kwargs):
                       the mask Tensor , the position that is 1 will be selected
 
     :return predict , truth: predict & truth after processing
-    '''
+    """
     if kwargs.get("mask") is None:
         return predict, truth
     mask = kwargs["mask"]
@@ -332,14 +341,14 @@ def mask(predict, truth, **kwargs):
 
 
 def make_mask(lens, tar_len):
-    '''to generate a mask that select [:lens[i]] for i-th element
+    """to generate a mask that select [:lens[i]] for i-th element
     embezzle from fastNLP.models.sequence_modeling.seq_mask
 
     :param lens		: list or LongTensor, [batch_size]
     :param tar_len	: int
 
     :return mask 	: ByteTensor
-    '''
+    """
     lens = torch.LongTensor(lens)
     mask = [torch.ge(lens, i + 1) for i in range(tar_len)]
     mask = torch.stack(mask, 1)
@@ -376,9 +385,11 @@ loss_function_name = {
 }
 
 
-class Loss(object):
-    """a Loss object is a callable object represents loss functions
+class LossFromTorch(object):
+    """a LossFromTorch object is a callable object represents loss functions
 
+        This class only helps you with loss functions from PyTorch.
+        It has nothing to do with Trainer.
     """
 
     def __init__(self, loss_name, pre_pro=[squash], **kwargs):
@@ -408,11 +419,11 @@ class Loss(object):
         self.pre_pro = [f if callable(f) else method_dict.get(f) for f in pre_pro]
 
     def add_pre_pro(self, func):
-        '''add a pre_pro function
+        """add a pre_pro function
 
         :param func: a function or str, methods to reform parameters before calculating loss
             the strings will be auto translated to pre-defined functions
-        '''
+        """
         if not callable(func):
             func = method_dict.get(func)
             if func is None:
@@ -421,12 +432,12 @@ class Loss(object):
 
     @staticmethod
     def _get_loss(loss_name, **kwargs):
-        '''Get loss function from torch
+        """Get loss function from torch
 
         :param loss_name: str, the name of loss function
         :param **kwargs: kwargs for torch loss function
         :return: A callable loss function object
-        '''
+        """
         loss_name = loss_name.strip().lower()
         loss_name = "".join(loss_name.split("_"))
 
@@ -435,19 +446,19 @@ class Loss(object):
         return loss_function_name[loss_name](**kwargs)
 
     def get(self):
-        '''This method exists just for make some existing codes run error-freely
-        '''
+        """This method exists just for make some existing codes run error-freely
+        """
         return self
 
     def __call__(self, predict, truth, **kwargs):
-        '''call a loss function
+        """Call a loss function
         predict and truth will be processed by pre_pro methods in order of addition
 
         :param predict	: Tensor, model output
         :param truth 	: Tensor, truth from dataset
         :param **kwargs : extra arguments, pass to pre_pro functions
             for example, if used unpad_mask() in pre_pro, there should be a kwarg named lens
-        '''
+        """
         for f in self.pre_pro:
             if f is None:
                 continue
diff --git a/fastNLP/core/metrics.py b/fastNLP/core/metrics.py
index 32c2306f..929d6ee1 100644
--- a/fastNLP/core/metrics.py
+++ b/fastNLP/core/metrics.py
@@ -308,6 +308,13 @@ def _prepare_metrics(metrics):
     return _metrics
 
 
+"""
+   Attention:  Codes below are not used in current FastNLP. 
+   However, it is useful. 
+
+"""
+
+
 def _conver_numpy(x):
     """convert input data to numpy array
 
diff --git a/fastNLP/core/optimizer.py b/fastNLP/core/optimizer.py
index 469c5632..dfcf83f9 100644
--- a/fastNLP/core/optimizer.py
+++ b/fastNLP/core/optimizer.py
@@ -11,6 +11,12 @@ class Optimizer(object):
 
 class SGD(Optimizer):
     def __init__(self, model_params=None, lr=0.01, momentum=0):
+        """
+
+        :param model_params: a generator. E.g. model.parameters() for PyTorch models.
+        :param float lr: learning rate. Default: 0.01
+        :param float momentum: momentum. Default: 0
+        """
         super(SGD, self).__init__(model_params, lr=lr, momentum=momentum)
 
     def construct_from_pytorch(self, model_params):
@@ -23,6 +29,12 @@ class SGD(Optimizer):
 
 class Adam(Optimizer):
     def __init__(self, model_params=None, lr=0.01, weight_decay=0):
+        """
+
+        :param model_params: a generator. E.g. model.parameters() for PyTorch models.
+        :param float lr: learning rate
+        :param float weight_decay:
+        """
         super(Adam, self).__init__(model_params, lr=lr, weight_decay=weight_decay)
 
     def construct_from_pytorch(self, model_params):
diff --git a/fastNLP/core/trainer.py b/fastNLP/core/trainer.py
index a3f81c00..c2bca3a2 100644
--- a/fastNLP/core/trainer.py
+++ b/fastNLP/core/trainer.py
@@ -140,7 +140,6 @@ class Trainer(object):
     def train(self):
         """Start Training.
 
-        :return:
         """
         try:
             if torch.cuda.is_available() and self.use_cuda:
@@ -216,14 +215,6 @@ class Trainer(object):
             pbar.close()
 
     def _print_train(self):
-        """
-
-        :param data_iterator:
-        :param model:
-        :param epoch:
-        :param start:
-        :return:
-        """
         epoch = 1
         start = time.time()
         while epoch <= self.n_epochs:
diff --git a/fastNLP/io/base_loader.py b/fastNLP/io/base_loader.py
index b67bc4ab..b0b0d864 100644
--- a/fastNLP/io/base_loader.py
+++ b/fastNLP/io/base_loader.py
@@ -29,19 +29,3 @@ class BaseLoader(object):
             with open(cache_path, 'wb') as f:
                 pickle.dump(obj, f)
             return obj
-
-
-class ToyLoader0(BaseLoader):
-    """
-        For CharLM
-    """
-
-    def __init__(self, data_path):
-        super(ToyLoader0, self).__init__(data_path)
-
-    def load(self):
-        with open(self.data_path, 'r') as f:
-            corpus = f.read().lower()
-        import re
-        corpus = re.sub(r"<unk>", "unk", corpus)
-        return corpus.split()
diff --git a/fastNLP/io/config_saver.py b/fastNLP/io/config_io.py
similarity index 52%
rename from fastNLP/io/config_saver.py
rename to fastNLP/io/config_io.py
index 49d6804d..52c5e789 100644
--- a/fastNLP/io/config_saver.py
+++ b/fastNLP/io/config_io.py
@@ -1,6 +1,152 @@
+import configparser
+import json
 import os
 
-from fastNLP.io.config_loader import ConfigSection, ConfigLoader
+from fastNLP.io.base_loader import BaseLoader
+
+
+class ConfigLoader(BaseLoader):
+    """loader for configuration files"""
+
+    def __init__(self, data_path=None):
+        super(ConfigLoader, self).__init__()
+        if data_path is not None:
+            self.config = self.parse(super(ConfigLoader, self).load(data_path))
+
+    @staticmethod
+    def parse(string):
+        raise NotImplementedError
+
+    @staticmethod
+    def load_config(file_path, sections):
+        """
+        :param file_path: the path of config file
+        :param sections: the dict of {section_name(string): Section instance}
+        Example:
+            test_args = ConfigSection()
+            ConfigLoader("config.cfg", "").load_config("./data_for_tests/config", {"POS_test": test_args})
+        :return: return nothing, but the value of attributes are saved in sessions
+        """
+        assert isinstance(sections, dict)
+        cfg = configparser.ConfigParser()
+        if not os.path.exists(file_path):
+            raise FileNotFoundError("config file {} not found. ".format(file_path))
+        cfg.read(file_path)
+        for s in sections:
+            attr_list = [i for i in sections[s].__dict__.keys() if
+                         not callable(getattr(sections[s], i)) and not i.startswith("__")]
+            if s not in cfg:
+                print('section %s not found in config file' % (s))
+                continue
+            gen_sec = cfg[s]
+            for attr in gen_sec.keys():
+                try:
+                    val = json.loads(gen_sec[attr])
+                    # print(s, attr, val, type(val))
+                    if attr in attr_list:
+                        assert type(val) == type(getattr(sections[s], attr)), \
+                            'type not match, except %s but got %s' % \
+                            (type(getattr(sections[s], attr)), type(val))
+                    """
+                            if attr in attr_list then check its type and
+                        update its value.
+                            else add a new attr in sections[s]
+                    """
+                    setattr(sections[s], attr, val)
+                except Exception as e:
+                    print("cannot load attribute %s in section %s"
+                          % (attr, s))
+                    pass
+
+
+class ConfigSection(object):
+
+    def __init__(self):
+        pass
+
+    def __getitem__(self, key):
+        """
+        :param key: str, the name of the attribute
+        :return attr: the value of this attribute
+            if key not in self.__dict__.keys():
+                return self[key]
+            else:
+                raise AttributeError
+        """
+        if key in self.__dict__.keys():
+            return getattr(self, key)
+        raise AttributeError("do NOT have attribute %s" % key)
+
+    def __setitem__(self, key, value):
+        """
+        :param key: str, the name of the attribute
+        :param value: the value of this attribute
+            if key not in self.__dict__.keys():
+                self[key] will be added
+            else:
+                self[key] will be updated
+        """
+        if key in self.__dict__.keys():
+            if not isinstance(value, type(getattr(self, key))):
+                raise AttributeError("attr %s except %s but got %s" %
+                                     (key, str(type(getattr(self, key))), str(type(value))))
+        setattr(self, key, value)
+
+    def __contains__(self, item):
+        """
+        :param item: The key of item.
+        :return: True if the key in self.__dict__.keys() else False.
+        """
+        return item in self.__dict__.keys()
+
+    def __eq__(self, other):
+        """Overwrite the == operator
+
+        :param other: Another ConfigSection() object which to be compared.
+        :return: True if value of each key in each ConfigSection() object are equal to the other, else False.
+        """
+        for k in self.__dict__.keys():
+            if k not in other.__dict__.keys():
+                return False
+            if getattr(self, k) != getattr(self, k):
+                return False
+
+        for k in other.__dict__.keys():
+            if k not in self.__dict__.keys():
+                return False
+            if getattr(self, k) != getattr(self, k):
+                return False
+
+        return True
+
+    def __ne__(self, other):
+        """Overwrite the != operator
+
+        :param other:
+        :return:
+        """
+        return not self.__eq__(other)
+
+    @property
+    def data(self):
+        return self.__dict__
+
+
+if __name__ == "__main__":
+    config = ConfigLoader('there is no data')
+
+    section = {'General': ConfigSection(), 'My': ConfigSection(), 'A': ConfigSection()}
+    """
+            General and My can be found in config file, so the attr and
+        value will be updated
+            A cannot be found in config file, so nothing will be done
+    """
+
+    config.load_config("../../test/data_for_tests/config", section)
+    for s in section:
+        print(s)
+        for attr in section[s].__dict__.keys():
+            print(s, attr, getattr(section[s], attr), type(getattr(section[s], attr)))
 
 
 class ConfigSaver(object):
@@ -125,7 +271,7 @@ class ConfigSaver(object):
                     # logger = create_logger(__name__, "./config_loader.log")
                     # logger.warning("section [%s] in config file [%s] has been changed" % (
                     #    section_name, self.file_path
-                    #))
+                    # ))
                     change_file = True
                     break
             if not change_file:
diff --git a/fastNLP/io/config_loader.py b/fastNLP/io/config_loader.py
deleted file mode 100644
index 66051e4d..00000000
--- a/fastNLP/io/config_loader.py
+++ /dev/null
@@ -1,149 +0,0 @@
-import configparser
-import json
-import os
-
-from fastNLP.io.base_loader import BaseLoader
-
-
-class ConfigLoader(BaseLoader):
-    """loader for configuration files"""
-
-    def __init__(self, data_path=None):
-        super(ConfigLoader, self).__init__()
-        if data_path is not None:
-            self.config = self.parse(super(ConfigLoader, self).load(data_path))
-
-    @staticmethod
-    def parse(string):
-        raise NotImplementedError
-
-    @staticmethod
-    def load_config(file_path, sections):
-        """
-        :param file_path: the path of config file
-        :param sections: the dict of {section_name(string): Section instance}
-        Example:
-            test_args = ConfigSection()
-            ConfigLoader("config.cfg", "").load_config("./data_for_tests/config", {"POS_test": test_args})
-        :return: return nothing, but the value of attributes are saved in sessions
-        """
-        assert isinstance(sections, dict)
-        cfg = configparser.ConfigParser()
-        if not os.path.exists(file_path):
-            raise FileNotFoundError("config file {} not found. ".format(file_path))
-        cfg.read(file_path)
-        for s in sections:
-            attr_list = [i for i in sections[s].__dict__.keys() if
-                         not callable(getattr(sections[s], i)) and not i.startswith("__")]
-            if s not in cfg:
-                print('section %s not found in config file' % (s))
-                continue
-            gen_sec = cfg[s]
-            for attr in gen_sec.keys():
-                try:
-                    val = json.loads(gen_sec[attr])
-                    # print(s, attr, val, type(val))
-                    if attr in attr_list:
-                        assert type(val) == type(getattr(sections[s], attr)), \
-                            'type not match, except %s but got %s' % \
-                            (type(getattr(sections[s], attr)), type(val))
-                    """
-                            if attr in attr_list then check its type and
-                        update its value.
-                            else add a new attr in sections[s]
-                    """
-                    setattr(sections[s], attr, val)
-                except Exception as e:
-                    print("cannot load attribute %s in section %s"
-                          % (attr, s))
-                    pass
-
-
-class ConfigSection(object):
-
-    def __init__(self):
-        pass
-
-    def __getitem__(self, key):
-        """
-        :param key: str, the name of the attribute
-        :return attr: the value of this attribute
-            if key not in self.__dict__.keys():
-                return self[key]
-            else:
-                raise AttributeError
-        """
-        if key in self.__dict__.keys():
-            return getattr(self, key)
-        raise AttributeError("do NOT have attribute %s" % key)
-
-    def __setitem__(self, key, value):
-        """
-        :param key: str, the name of the attribute
-        :param value: the value of this attribute
-            if key not in self.__dict__.keys():
-                self[key] will be added
-            else:
-                self[key] will be updated
-        """
-        if key in self.__dict__.keys():
-            if not isinstance(value, type(getattr(self, key))):
-                raise AttributeError("attr %s except %s but got %s" %
-                                     (key, str(type(getattr(self, key))), str(type(value))))
-        setattr(self, key, value)
-
-    def __contains__(self, item):
-        """
-        :param item: The key of item.
-        :return: True if the key in self.__dict__.keys() else False.
-        """
-        return item in self.__dict__.keys()
-
-    def __eq__(self, other):
-        """Overwrite the == operator
-
-        :param other: Another ConfigSection() object which to be compared.
-        :return: True if value of each key in each ConfigSection() object are equal to the other, else False.
-        """
-        for k in self.__dict__.keys():
-            if k not in other.__dict__.keys():
-                return False
-            if getattr(self, k) != getattr(self, k):
-                return False
-
-        for k in other.__dict__.keys():
-            if k not in self.__dict__.keys():
-                return False
-            if getattr(self, k) != getattr(self, k):
-                return False
-
-        return True
-
-    def __ne__(self, other):
-        """Overwrite the != operator
-
-        :param other:
-        :return:
-        """
-        return not self.__eq__(other)
-
-    @property
-    def data(self):
-        return self.__dict__
-
-
-if __name__ == "__main__":
-    config = ConfigLoader('there is no data')
-
-    section = {'General': ConfigSection(), 'My': ConfigSection(), 'A': ConfigSection()}
-    """
-            General and My can be found in config file, so the attr and
-        value will be updated
-            A cannot be found in config file, so nothing will be done
-    """
-
-    config.load_config("../../test/data_for_tests/config", section)
-    for s in section:
-        print(s)
-        for attr in section[s].__dict__.keys():
-            print(s, attr, getattr(section[s], attr), type(getattr(section[s], attr)))
diff --git a/fastNLP/io/dataset_loader.py b/fastNLP/io/dataset_loader.py
index 79cb30ad..fc2edb23 100644
--- a/fastNLP/io/dataset_loader.py
+++ b/fastNLP/io/dataset_loader.py
@@ -1,4 +1,3 @@
-#TODO: need fix for current DataSet
 import os
 
 from fastNLP.core.dataset import DataSet
@@ -20,8 +19,7 @@ def convert_seq_dataset(data):
     """
     dataset = DataSet()
     for word_seq in data:
-        x = TextField(word_seq, is_target=False)
-        dataset.append(Instance(word_seq=x))
+        dataset.append(Instance(word_seq=word_seq))
     return dataset
 
 
@@ -40,11 +38,7 @@ def convert_seq2tag_dataset(data):
     """
     dataset = DataSet()
     for sample in data:
-        word_seq, label = sample[0], sample[1]
-        ins = Instance()
-        ins.add_field("word_seq", TextField(word_seq, is_target=False)) \
-            .add_field("label", LabelField(label, is_target=True))
-        dataset.append(ins)
+        dataset.append(Instance(word_seq=sample[0], label=sample[1]))
     return dataset
 
 
@@ -63,11 +57,7 @@ def convert_seq2seq_dataset(data):
     """
     dataset = DataSet()
     for sample in data:
-        word_seq, label_seq = sample[0], sample[1]
-        ins = Instance()
-        ins.add_field("word_seq", TextField(word_seq, is_target=False)) \
-            .add_field("label_seq", TextField(label_seq, is_target=True))
-        dataset.append(ins)
+        dataset.append(Instance(word_seq=sample[0], label_seq=sample[1]))
     return dataset
 
 
@@ -273,85 +263,6 @@ class ClassDataSetLoader(DataSetLoader):
         return convert_seq2tag_dataset(data)
 
 
-@DataSet.set_reader('read_conll')
-class ConllLoader(DataSetLoader):
-    """loader for conll format files"""
-
-    def __init__(self):
-        """
-        :param str data_path: the path to the conll data set
-        """
-        super(ConllLoader, self).__init__()
-
-    def load(self, data_path):
-        """
-        :return: list lines: all lines in a conll file
-        """
-        with open(data_path, "r", encoding="utf-8") as f:
-            lines = f.readlines()
-        data = self.parse(lines)
-        return self.convert(data)
-
-    @staticmethod
-    def parse(lines):
-        """
-        :param list lines:a list containing all lines in a conll file.
-        :return: a 3D list
-        """
-        sentences = list()
-        tokens = list()
-        for line in lines:
-            if line[0] == "#":
-                # skip the comments
-                continue
-            if line == "\n":
-                sentences.append(tokens)
-                tokens = []
-                continue
-            tokens.append(line.split())
-        return sentences
-
-    def convert(self, data):
-        pass
-
-
-@DataSet.set_reader('read_lm')
-class LMDataSetLoader(DataSetLoader):
-    """Language Model Dataset Loader
-
-        This loader produces data for language model training in a supervised way.
-        That means it has X and Y.
-
-    """
-
-    def __init__(self):
-        super(LMDataSetLoader, self).__init__()
-
-    def load(self, data_path):
-        if not os.path.exists(data_path):
-            raise FileNotFoundError("file {} not found.".format(data_path))
-        with open(data_path, "r", encoding="utf=8") as f:
-            text = " ".join(f.readlines())
-        tokens = text.strip().split()
-        data = self.sentence_cut(tokens)
-        return self.convert(data)
-
-    def sentence_cut(self, tokens, sentence_length=15):
-        start_idx = 0
-        data_set = []
-        for idx in range(len(tokens) // sentence_length):
-            x = tokens[start_idx * idx: start_idx * idx + sentence_length]
-            y = tokens[start_idx * idx + 1: start_idx * idx + sentence_length + 1]
-            if start_idx * idx + sentence_length + 1 >= len(tokens):
-                # ad hoc
-                y.extend(["<unk>"])
-            data_set.append([x, y])
-        return data_set
-
-    def convert(self, data):
-        pass
-
-
 @DataSet.set_reader('read_people_daily')
 class PeopleDailyCorpusLoader(DataSetLoader):
     """
@@ -403,10 +314,19 @@ class PeopleDailyCorpusLoader(DataSetLoader):
             pos_tag_examples.append([sent_words, sent_pos_tag])
             ner_examples.append([sent_words, sent_ner])
         # List[List[List[str], List[str]]]
-        return pos_tag_examples, ner_examples
+        # ner_examples not used
+        return self.convert(pos_tag_examples)
 
     def convert(self, data):
-        pass
+        data_set = DataSet()
+        for item in data:
+            sent_words, sent_pos_tag = item[0], item[1]
+            data_set.append(Instance(words=sent_words, tags=sent_pos_tag))
+        data_set.apply(lambda ins: len(ins), new_field_name="seq_len")
+        data_set.set_target("tags")
+        data_set.set_input("sent_words")
+        data_set.set_input("seq_len")
+        return data_set
 
 
 class SNLIDataSetLoader(DataSetLoader):
@@ -462,17 +382,13 @@ class SNLIDataSetLoader(DataSetLoader):
         for example in data:
             p, h, l = example
             # list, list, str
-            x1 = TextField(p, is_target=False)
-            x2 = TextField(h, is_target=False)
-            x1_len = TextField([1] * len(p), is_target=False)
-            x2_len = TextField([1] * len(h), is_target=False)
-            y = LabelField(l, is_target=True)
             instance = Instance()
-            instance.add_field("premise", x1)
-            instance.add_field("hypothesis", x2)
-            instance.add_field("premise_len", x1_len)
-            instance.add_field("hypothesis_len", x2_len)
-            instance.add_field("truth", y)
+            instance.add_field("premise", p)
+            instance.add_field("hypothesis", h)
+            instance.add_field("truth", l)
             data_set.append(instance)
-
+        data_set.apply(lambda ins: len(ins["premise"]), new_field_name="premise_len")
+        data_set.apply(lambda ins: len(ins["hypothesis"]), new_field_name="hypothesis_len")
+        data_set.set_input("premise", "hypothesis", "premise_len", "hypothesis_len")
+        data_set.set_target("truth")
         return data_set
diff --git a/fastNLP/io/model_saver.py b/fastNLP/io/model_io.py
similarity index 51%
rename from fastNLP/io/model_saver.py
rename to fastNLP/io/model_io.py
index fd391f69..e1264b47 100644
--- a/fastNLP/io/model_saver.py
+++ b/fastNLP/io/model_io.py
@@ -1,5 +1,32 @@
 import torch
 
+from fastNLP.io.base_loader import BaseLoader
+
+
+class ModelLoader(BaseLoader):
+    """
+        Loader for models.
+    """
+
+    def __init__(self):
+        super(ModelLoader, self).__init__()
+
+    @staticmethod
+    def load_pytorch(empty_model, model_path):
+        """
+        Load model parameters from .pkl files into the empty PyTorch model.
+        :param empty_model: a PyTorch model with initialized parameters.
+        :param model_path: str, the path to the saved model.
+        """
+        empty_model.load_state_dict(torch.load(model_path))
+
+    @staticmethod
+    def load_pytorch_model(model_path):
+        """Load the entire model.
+
+        """
+        return torch.load(model_path)
+
 
 class ModelSaver(object):
     """Save a model
@@ -8,6 +35,7 @@ class ModelSaver(object):
             saver.save_pytorch(model)
 
     """
+
     def __init__(self, save_path):
         """
 
diff --git a/fastNLP/io/model_loader.py b/fastNLP/io/model_loader.py
deleted file mode 100644
index afa05b93..00000000
--- a/fastNLP/io/model_loader.py
+++ /dev/null
@@ -1,28 +0,0 @@
-import torch
-
-from fastNLP.io.base_loader import BaseLoader
-
-
-class ModelLoader(BaseLoader):
-    """
-        Loader for models.
-    """
-
-    def __init__(self):
-        super(ModelLoader, self).__init__()
-
-    @staticmethod
-    def load_pytorch(empty_model, model_path):
-        """
-        Load model parameters from .pkl files into the empty PyTorch model.
-        :param empty_model: a PyTorch model with initialized parameters.
-        :param model_path: str, the path to the saved model.
-        """
-        empty_model.load_state_dict(torch.load(model_path))
-
-    @staticmethod
-    def load_pytorch_model(model_path):
-        """Load the entire model.
-
-        """
-        return torch.load(model_path)
diff --git a/reproduction/Biaffine_parser/infer.py b/reproduction/Biaffine_parser/infer.py
index 7d05c62b..8ebfa91c 100644
--- a/reproduction/Biaffine_parser/infer.py
+++ b/reproduction/Biaffine_parser/infer.py
@@ -5,7 +5,7 @@ sys.path.extend(['/home/yfshao/workdir/dev_fastnlp'])
 
 from fastNLP.api.processor import *
 from fastNLP.models.biaffine_parser import BiaffineParser
-from fastNLP.io.config_loader import ConfigSection, ConfigLoader
+from fastNLP.io.config_io import ConfigSection, ConfigLoader
 
 import _pickle as pickle
 import torch
diff --git a/reproduction/Biaffine_parser/run.py b/reproduction/Biaffine_parser/run.py
index 15dd3d4f..0519201a 100644
--- a/reproduction/Biaffine_parser/run.py
+++ b/reproduction/Biaffine_parser/run.py
@@ -13,11 +13,10 @@ from fastNLP.core.vocabulary import Vocabulary
 from fastNLP.core.dataset import DataSet
 from fastNLP.core.field import TextField, SeqLabelField
 from fastNLP.core.tester import Tester
-from fastNLP.io.config_loader import ConfigLoader, ConfigSection
-from fastNLP.io.model_loader import ModelLoader
+from fastNLP.io.config_io import ConfigLoader, ConfigSection
+from fastNLP.io.model_io import ModelLoader, ModelSaver
 from fastNLP.io.embed_loader import EmbedLoader
 from fastNLP.models.biaffine_parser import BiaffineParser
-from fastNLP.io.model_saver import ModelSaver
 
 BOS = '<BOS>'
 EOS = '<EOS>'
diff --git a/reproduction/LSTM+self_attention_sentiment_analysis/main.py b/reproduction/LSTM+self_attention_sentiment_analysis/main.py
index 2a64c8d3..61ab79f4 100644
--- a/reproduction/LSTM+self_attention_sentiment_analysis/main.py
+++ b/reproduction/LSTM+self_attention_sentiment_analysis/main.py
@@ -2,8 +2,8 @@ import torch.nn.functional as F
 
 from fastNLP.core.trainer import ClassificationTrainer
 from fastNLP.core.utils import ClassPreprocess as Preprocess
-from fastNLP.io.config_loader import ConfigLoader
-from fastNLP.io.config_loader import ConfigSection
+from fastNLP.io.config_io import ConfigLoader
+from fastNLP.io.config_io import ConfigSection
 from fastNLP.io.dataset_loader import ClassDataSetLoader as Dataset_loader
 from fastNLP.models.base_model import BaseModel
 from fastNLP.modules.aggregator.self_attention import SelfAttention
diff --git a/reproduction/chinese_word_segment/run.py b/reproduction/chinese_word_segment/run.py
index 7dd5091a..e7804bae 100644
--- a/reproduction/chinese_word_segment/run.py
+++ b/reproduction/chinese_word_segment/run.py
@@ -3,12 +3,11 @@ import sys
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '../..'))
 
-from fastNLP.io.config_loader import ConfigLoader, ConfigSection
+from fastNLP.io.config_io import ConfigLoader, ConfigSection
 from fastNLP.core.trainer import SeqLabelTrainer
 from fastNLP.io.dataset_loader import BaseLoader, TokenizeDataSetLoader
 from fastNLP.core.utils import load_pickle
-from fastNLP.io.model_saver import ModelSaver
-from fastNLP.io.model_loader import ModelLoader
+from fastNLP.io.model_io import ModelLoader, ModelSaver
 from fastNLP.core.tester import SeqLabelTester
 from fastNLP.models.sequence_modeling import AdvSeqLabel
 from fastNLP.core.predictor import SeqLabelInfer
diff --git a/setup.py b/setup.py
index 0da887a3..a8b4834e 100644
--- a/setup.py
+++ b/setup.py
@@ -12,12 +12,12 @@ with open('requirements.txt', encoding='utf-8') as f:
     reqs = f.read()
 
 setup(
-    name='fastNLP',
+    name='FastNLP',
     version='0.1.1',
     description='fastNLP: Deep Learning Toolkit for NLP, developed by Fudan FastNLP Team',
     long_description=readme,
     license=license,
-    author='fudanNLP',
+    author='FudanNLP',
     python_requires='>=3.5',
     packages=find_packages(),
     install_requires=reqs.strip().split('\n'),
diff --git a/test/api/test_processor.py b/test/api/test_processor.py
new file mode 100644
index 00000000..fa6133b9
--- /dev/null
+++ b/test/api/test_processor.py
@@ -0,0 +1,12 @@
+import unittest
+
+from fastNLP.api.processor import FullSpaceToHalfSpaceProcessor
+from fastNLP.core.dataset import DataSet
+
+
+class TestProcessor(unittest.TestCase):
+    def test_FullSpaceToHalfSpaceProcessor(self):
+        ds = DataSet({"word": ["０0, u１, u), (u２, u2"]})
+        proc = FullSpaceToHalfSpaceProcessor("word")
+        ds = proc(ds)
+        self.assertTrue(ds.field_arrays["word"].content, ["00, u1, u), (u2, u2"])
diff --git a/test/core/test_loss.py b/test/core/test_loss.py
index a7c303e2..52860b36 100644
--- a/test/core/test_loss.py
+++ b/test/core/test_loss.py
@@ -45,7 +45,7 @@ class TestLoss(unittest.TestCase):
         # 验证squash()的正确性
 
         log = math.log
-        loss_func = loss.Loss("nll")
+        loss_func = loss.LossFromTorch("nll")
 
         y = tc.Tensor(
             [
@@ -129,7 +129,7 @@ class TestLoss(unittest.TestCase):
         lens = [4, 2, 1]
         y = tc.log(y)
 
-        loss_func = loss.Loss("nll", pre_pro=["unpad"])
+        loss_func = loss.LossFromTorch("nll", pre_pro=["unpad"])
         los = loss_func(y, gy, lens=lens)
 
         r = -log(.1) - log(.3) - log(.5) - log(.5) - log(.3) - log(.7) - log(.1)
@@ -169,7 +169,7 @@ class TestLoss(unittest.TestCase):
 
         lens = [2, 4, 2]
 
-        loss_func = loss.Loss("nll", pre_pro=["mask"])
+        loss_func = loss.LossFromTorch("nll", pre_pro=["mask"])
         los = loss_func(y, gy, mask=mask)
 
         los2 = loss_func(y, gy, mask=loss.make_mask(lens, gy.size()[-1]))
@@ -205,7 +205,7 @@ class TestLoss(unittest.TestCase):
 
         y = tc.log(y)
 
-        loss_func = loss.Loss("nll", pre_pro=["unpad_mask"])
+        loss_func = loss.LossFromTorch("nll", pre_pro=["unpad_mask"])
         los = loss_func(y, gy, lens=lens)
 
         r = -log(.1) - log(.3) - log(.5) - log(.5) - log(.3) - log(.7) - log(.1)
@@ -235,7 +235,7 @@ class TestLoss(unittest.TestCase):
         lens = [4, 2, 1]
         y = tc.log(y)
 
-        loss_func = loss.Loss("nll", pre_pro=[], weight=tc.Tensor([1, 1, 0]))
+        loss_func = loss.LossFromTorch("nll", pre_pro=[], weight=tc.Tensor([1, 1, 0]))
         loss_func.add_pre_pro("unpad_mask")
         los = loss_func(y, gy, lens=lens)
 
diff --git a/test/io/test_config_saver.py b/test/io/test_config_saver.py
index 4a223f91..f29097c5 100644
--- a/test/io/test_config_saver.py
+++ b/test/io/test_config_saver.py
@@ -1,8 +1,7 @@
 import os
 import unittest
 
-from fastNLP.io.config_loader import ConfigSection, ConfigLoader
-from fastNLP.io.config_saver import ConfigSaver
+from fastNLP.io.config_io import ConfigSection, ConfigLoader, ConfigSaver
 
 
 class TestConfigSaver(unittest.TestCase):