<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def direct_messages(self, delegate, params={}, extra_args=None):
 """Get direct messages for the authenticating user. Search results are returned one message at a time a DirectMessage objects"""

        return self.__get('/direct_messages.xml', delegate, params,
                          txml.Direct, extra_args=extra_args)