class_docstr: Interface for input creator.
  
  The `InputCreator` class is an abstract class to implement `create_inputs` in
  `ModelBuilder` in tfr.keras.
  
  To be implemented by subclasses:
  
    * `__call__()`: Contains the logic to create `tf.keras.Input` for context
    and example inputs.
  
  Example subclass implementation:
  
  ```python
  class SimpleInputCreator(InputCreator):
  
    def __call__(self):
      return {}, {"example_feature_1": tf.keras.Input((1,), dtype=tf.float32)}
  ```
docstr: Invokes the `InputCreator` instance.
  
  Returns:
    A tuple of two dicts which map the context and example feature keys to
      the corresponding `tf.keras.Input`.
docstr_tok: ["Invokes","the","`","InputCreator","`","instance",".","Returns",":","A","tuple","of","two","dicts","which","map","the","context","and","example","feature","keys","to","the","corresponding","`","tf.keras.Input","`","."]
code: def __call__(self) -> Tuple[TensorDict, TensorDict]:
      """Invokes the `InputCreator` instance.
  
      Returns:
        A tuple of two dicts which map the context and example feature keys to
          the corresponding `tf.keras.Input`.
      """
      raise NotImplementedError("Calling an abstract method.")
  
imports: import abc
  from typing import Any, Callable, Dict, List, Optional, Tuple, Union
  from absl import logging
  import tensorflow
  from tensorflow_ranking.python.keras import feature
  from tensorflow_ranking.python.keras import layers
label_desc: Use image node_id 1 for calling the InputCreator obj's underlying member method code with example usage: obj.__call__() without return types