def _list_global_ips_by_identifier(self, identifier):
        """Returns a list of IDs of the global IP matching the identifier.

        :param string identifier: The identifier to look up
        :returns: List of matching IDs
        """
        results = self.list_global_ips(identifier=identifier, mask='id')
        return [result['id'] for result in results]
Returns a list of IDs of the global IP matching the identifier.

        :param string identifier: The identifier to look up
        :returns: List of matching IDs