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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_sorting_message(request, key):
 """Parses the reverse query into a list of ClientSortControls protobuf messages. """

        control_list = []
        reverse = request.url.query.get('reverse', None)
        if reverse is None:
            return control_list

        if reverse.lower() == "":
            control_list.append(client_list_control_pb2.ClientSortControls(
                reverse=True,
                keys=key.split(",")
            ))
        elif reverse.lower() != 'false':
            control_list.append(client_list_control_pb2.ClientSortControls(
                reverse=True,
                keys=reverse.split(",")
            ))

        return control_list