def verify_headers(self, check_presence=True, **kwargs):
        """
        Check that a set of particular header claim are present and has
        specific values

        :param kwargs: The claim/value sets as a dictionary
        :return: True if the claim that appears in the header has the
            prescribed values. If a claim is not present in the header and
            check_presence is True then False is returned.
        """
        for key, val in kwargs.items():
            try:
                _ok = self.verify_header(key, val)
            except KeyError:
                if check_presence:
                    return False
                else:
                    pass
            else:
                if not _ok:
                    return False
        return True
Check that a set of particular header claim are present and has
        specific values

        :param kwargs: The claim/value sets as a dictionary
        :return: True if the claim that appears in the header has the
            prescribed values. If a claim is not present in the header and
            check_presence is True then False is returned.