keras/src/layers/preprocessing/feature_space.py/FeatureSpace/string_categorical
class FeatureSpace:    def string_categorical(
        cls,
        max_tokens=None,
        num_oov_indices=1,
        output_mode="one_hot",
        name=None,
    ):
        name = name or auto_name("string_categorical")
        preprocessor = layers.StringLookup(
            name=f"{name}_preprocessor",
            max_tokens=max_tokens,
            num_oov_indices=num_oov_indices,
        )
        return Feature(
            dtype="string", preprocessor=preprocessor, output_mode=output_mode
        )