[FIX] fix flake8 error

tests/conftest.py

@@ -2,15 +2,11 @@ import pytest
 import torch
 import torch.nn as nn
 import torch.optim as optim
-import os
-import sys
-
-sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 from abl.learning import BasicNN
 from abl.reasoning import GroundKB, KBBase, PrologKB, Reasoner
 from abl.structures import ListData
-from examples.models.nn import LeNet5
+from ..examples.models.nn import LeNet5
 
 
 # Fixture for BasicNN instance