code: def modify_ip(self, ip_addr, ptr_record):
          
          body = {
              'ip_address': {
                  'ptr_record': ptr_record
              }
          }
  
          res = self.request('PUT', '/ip_address/' + str(ip_addr), body)
          return IPAddress(cloud_manager=self, **res['ip_address'])
docs: Modify an IP address' ptr-record (Reverse DNS).
  
          Accepts an IPAddress instance (object) or its address (string).