diff --git a/src/TensorFlowNET.Core/Framework/meta_graph.py.cs b/src/TensorFlowNET.Core/Framework/meta_graph.py.cs
index 9e40bb46..447b7835 100644
--- a/src/TensorFlowNET.Core/Framework/meta_graph.py.cs
+++ b/src/TensorFlowNET.Core/Framework/meta_graph.py.cs
@@ -134,7 +134,8 @@ namespace Tensorflow
                                         }
                                         break;
                                     default:
-                                        throw new NotImplementedException("import_scoped_meta_graph_with_return_elements");
+                                        Console.WriteLine("import_scoped_meta_graph_with_return_elements");
+                                        continue;
                                 }
                             }
                         }
diff --git a/src/TensorFlowNET.Core/Train/Optimizer.cs b/src/TensorFlowNET.Core/Train/Optimizer.cs
index 6c13ac20..ef042e8f 100644
--- a/src/TensorFlowNET.Core/Train/Optimizer.cs
+++ b/src/TensorFlowNET.Core/Train/Optimizer.cs
@@ -199,8 +199,8 @@ namespace Tensorflow
 
                 if (!tf.context.executing_eagerly())
                 {
-                    var train_op = ops.get_collection_ref(ops.GraphKeys.TRAIN_OP) as List<object>;
-                    if (!train_op.Contains(apply_updates))
+                    var train_op = ops.get_collection_ref(ops.GraphKeys.TRAIN_OP) as List<ITensorOrOperation>;
+                    if (train_op != null && train_op.Contains(apply_updates))
                         train_op.Add(apply_updates);
                 }