@staticmethod
def _validate_fp_type(fp_type: str) ->None:
    """Validate that the delta fixed point type is supported."""
    if fp_type not in {'safe_linear', 'linear', 'safe_nonlinear', 'nonlinear'}:
        raise ValueError(
            "fp_type must be 'safe_linear', 'linear', 'safe_nonlinear', or 'nonlinear'."
            )
