Running the training loop

Hello When I try to run the training loop I get the following error. Could you help me

/usr/local/lib/python3.7/dist-packages/tensorflow/python/framework/ in autograph_handler(*args, **kwargs)
1123 recursive=True,
1124 optional_features=autograph_options,
→ 1125 user_requested=True,
1126 ))
1127 except Exception as e: # pylint:disable=broad-except

TypeError: in user code:

File "<ipython-input-63-38c196ad1363>", line 44, in train_step_fn  *
    prediction_dict = model.predict(preprocessed_image_tensor, true_shape_tensor)

TypeError: apply_gradients() missing 1 required positional argument: 'grads_and_vars'

Check the train_step_fn function the error says the apply_gradients is missing a parameter or maybe you are not calculating the parameters that go inside it properly.