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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_changes_since(self, change_number, app_changes=True, package_changes=False):
 """Get changes since a change number :param change_number: change number to use as stating point :type change_number: :class:`int` :param app_changes: whether to inclued app changes :type app_changes: :class:`bool` :param package_changes: whether to inclued package changes :type package_changes: :class:`bool` :return: `CMsgClientPICSChangesSinceResponse <https://github.com/ValvePython/steam/blob/39627fe883feeed2206016bacd92cf0e4580ead6/protobufs/steammessages_clientserver.proto#L1171-L1191>`_ :rtype: proto message instance, or :class:`None` on timeout """

        return self.send_job_and_wait(MsgProto(EMsg.ClientPICSChangesSinceRequest),
                                      {
                                       'since_change_number': change_number,
                                       'send_app_info_changes': app_changes,
                                       'send_package_info_changes': package_changes,
                                      },
                                      timeout=15
                                     )