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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 get_jwt_verify_keys(self, jwt, **kwargs):
 """ Get keys from this key jar based on information in a JWS. These keys should be usable to verify the signed JWT. :param jwt: A cryptojwt.jwt.JWT instance :param kwargs: Other key word arguments :return: list of usable keys """


        try:
            allow_missing_kid = kwargs['allow_missing_kid']
        except KeyError:
            allow_missing_kid = False

        try:
            _key_type = jws_alg2keytype(jwt.headers['alg'])
        except KeyError:
            _key_type = ''

        try:
            _kid = jwt.headers['kid']
        except KeyError:
            logger.info('Missing kid')
            _kid = ''

        try:
            nki = kwargs['no_kid_issuer']
        except KeyError:
            nki = {}

        _payload = jwt.payload()

        try:
            _iss = _payload['iss']
        except KeyError:
            try:
                _iss = kwargs['iss']
            except KeyError:
                _iss = ''

        if _iss:
            # First extend the key jar iff allowed
            if "jku" in jwt.headers and _iss:
                if not self.find(jwt.headers["jku"], _iss):
                    # This is really questionable
                    try:
                        if kwargs["trusting"]:
                            self.add_url(_iss, jwt.headers["jku"])
                    except KeyError:
                        pass

            keys = self._add_key([], _iss, 'sig', _key_type,
                                 _kid, nki, allow_missing_kid)

            if _key_type == 'oct':
                keys.extend(self.get(key_use='sig', owner='',
                                     key_type=_key_type))
        else:  # No issuer, just use all keys I have
            keys = self.get(key_use='sig', owner='', key_type=_key_type)

        # Only want the appropriate keys.
        keys = [k for k in keys if k.appropriate_for('verify')]
        return keys