src/transformers/pipelines/text2text_generation.py/Text2TextGenerationPipeline/_sanitize_parameters
class Text2TextGenerationPipeline:    def _sanitize_parameters(
        self,
        return_tensors=None,
        return_text=None,
        return_type=None,
        clean_up_tokenization_spaces=None,
        truncation=None,
        **generate_kwargs
    ):
        preprocess_params = {}
        if truncation is not None:
            preprocess_params["truncation"] = truncation

        forward_params = generate_kwargs

        postprocess_params = {}
        if return_tensors is not None and return_type is None:
            return_type = ReturnType.TENSORS if return_tensors else ReturnType.TEXT
        if return_type is not None:
            postprocess_params["return_type"] = return_type

        if clean_up_tokenization_spaces is not None:
            postprocess_params["clean_up_tokenization_spaces"] = clean_up_tokenization_spaces

        return preprocess_params, forward_params, postprocess_params