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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def verify_compact(self, jws=None, keys=None, allow_none=False, sigalg=None):
 """ Verify a JWT signature :param jws: A signed JSON Web Token :param keys: A list of keys that can possibly be used to verify the signature :param allow_none: If signature algorithm 'none' is allowed :param sigalg: Expected sigalg :return: Dictionary with 2 keys 'msg' required, 'key' optional """

        return self.verify_compact_verbose(jws, keys, allow_none, sigalg)['msg']