Strange error with early stopping

This seems a very stupid question, but I hope you would help me to point out where goes wrong.

I simply copy the code for early stopping from the docs as this:

metrics_callback = MetricsCallback()
early_stop_callback = EarlyStopping(
   monitor='val_acc',
   min_delta=0.00,
   patience=50,
   verbose=False,
   mode='max'
)

But it complaints:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-9-a3e7c79183f7> in <module>
      5    patience=50,
      6    verbose=False,
----> 7    mode='max'
      8 )

TypeError: __init__() got an unexpected keyword argument 'monitor'

I am using the version of 1.0.7. From the source code, one clearly sees these are keyword arguments but I can only treat them as positional arguments. Why is that?

Thanks a lot!