'No loss found. You may have forgotten to provide a `loss` argument '

[xkluan]

When I test the getting-started on https://colab.research.google.com/github/kipoi/kipoiseq/blob/master/notebooks/getting-started.ipynb . I found that the run the cell "model.fit_generator(iterator, steps_per_epoch=len(dl)//batch_size, epochs=10)", there is an error occured. That said as below:

ValueError: in user code:

File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 1021, in train_function  *
    return step_function(self, iterator)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 1010, in step_function  **
    outputs = model.distribute_strategy.run(run_step, args=(data,))
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 1000, in run_step  **
    outputs = model.train_step(data)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 861, in train_step
    self._validate_target_and_loss(y, loss)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 828, in _validate_target_and_loss
    'No loss found. You may have forgotten to provide a `loss` argument '

ValueError: No loss found. You may have forgotten to provide a `loss` argument in the `compile()` method. 

However, I have set the loss parameter in model.compile function:
model.compile(optimizer = 'adam', loss = ['binary_crossentropy'], metrics = ['acc'])

I want to know why this will happen.