@classmethod
def _is_optional_claim(cls, claim_name: str) ->bool:
    """
            Determine if the given claim is optional and may thus be empty or missing in the claim set.

            A claim is optional if it is listed in :attr:`_optional_claims`.

            :param claim_name: The name of the claim to check.
            :return: `True` if the given claim is optional, `False` otherwise.
        """
    return claim_name in cls._optional_claims
