docs: def get_comments_of_letter_per_page(self, letter_id, per_page=1000, page=1):
          """
          Get comments of letter per page
  
          :param letter_id: the letter id
          :param per_page: How many objects per page. Default: 1000
          :param page: Which page. Default: 1
          :return: list
          """
          return self._get_resource_per_page(
              resource=LETTER_COMMENTS,
              per_page=per_page,
              page=page,
              params={'letter_id': letter_id},
          )