code: def get_user(self, user_name=None):
          
          params = {}
          if user_name:
              params['UserName'] = user_name
          return self.get_response('GetUser', params)
docs: Retrieve information about the specified user.
  
          If the user_name is not specified, the user_name is determined
          implicitly based on the AWS Access Key ID used to sign the request.
  
          :type user_name: string
          :param user_name: The name of the user to delete.
                            If not specified, defaults to user making
                            request.