keras/src/layers/preprocessing/feature_space.py/Feature/__init__
class Feature:    def __init__(self, dtype, preprocessor, output_mode):
        if output_mode not in {"int", "one_hot", "float"}:
            raise ValueError(
                "Invalid value for argument `output_mode`. "
                "Expected one of {'int', 'one_hot', 'float'}. "
                f"Received: output_mode={output_mode}"
            )
        self.dtype = dtype
        if isinstance(preprocessor, dict):
            preprocessor = serialization_lib.deserialize_keras_object(
                preprocessor
            )
        self.preprocessor = preprocessor
        self.output_mode = output_mode