code: def get_contacts_of_client_per_page(self, client_id, per_page=1000, page=1):
          
          return self._get_resource_per_page(
              resource=CONTACTS,
              per_page=per_page,
              page=page,
              params={'client_id': client_id},
          )
docs: Get contacts of client per page
  
          :param client_id: the client id
          :param per_page: How many objects per page. Default: 1000
          :param page: Which page. Default: 1
          :return: list