message: `tf.keras.backend.placeholder` does not raise a `ValueError`, If called with eager execution.
diff: @@ -1306,7 +1306,6 @@ def placeholder(shape=None,
  [guide](https://www.tensorflow.org/guide/ragged_tensors).
  Raises:
  - ValueError: If called with eager execution
  ValueError: If called with sparse = True and ragged = True.
  Returns:
  