Remove type remark from readme, the assertion alone should suffice an…

…d is more DRY

README.md

@@ -86,7 +86,7 @@ Would you like to build/train a model using Keras/Python? And would you like to
 Usage
 -----
 
-1) Use Keras/Python to build (`model.compile(...)`), train (`model.fit(...)`) and test (`model.evaluate(...)`) your model as usual. Then save it to a single file using `model.save('....keras')`. The `image_data_format` in your model must be `channels_last`, which is the default when using the TensorFlow backend. Models created with a different `image_data_format` and other backends are not supported. The model must be of type `tensorflow.keras.models.Model`.
+1) Use Keras/Python to build (`model.compile(...)`), train (`model.fit(...)`) and test (`model.evaluate(...)`) your model as usual. Then save it to a single file using `model.save('....keras')`. The `image_data_format` in your model must be `channels_last`, which is the default when using the TensorFlow backend. Models created with a different `image_data_format` and other backends are not supported.
 
 2) Now convert it to the frugally-deep file format with `keras_export/convert_model.py`