docs: def get_mock_personalization_dict():
      """Get a dict of personalization mock."""
      mock_pers = dict()
  
      mock_pers['to_list'] = [To("test1@example.com",
                                    "Example User"),
                              To("test2@example.com",
                                    "Example User")]
  
      mock_pers['cc_list'] = [To("test3@example.com",
                                    "Example User"),
                              To("test4@example.com",
                                    "Example User")]
  
      mock_pers['bcc_list'] = [To("test5@example.com"),
                               To("test6@example.com")]
  
      mock_pers['subject'] = ("Hello World from the Personalized "
                              "SendGrid Python Library")
  
      mock_pers['headers'] = [Header("X-Test", "test"),
                              Header("X-Mock", "true")]
  
      mock_pers['substitutions'] = [Substitution("%name%", "Example User"),
                                    Substitution("%city%", "Denver")]
  
      mock_pers['custom_args'] = [CustomArg("user_id", "343"),
                                  CustomArg("type", "marketing")]
  
      mock_pers['send_at'] = 1443636843
      return mock_pers