code: def send_custom_host_notification(self, host, options, author, comment):
          
          logger.warning("The external command 'SEND_CUSTOM_HOST_NOTIFICATION' "
                         "is not currently implemented in Alignak. If you really need it, "
                         "request for its implementation in the project repository: "
                         "https://github.com/Alignak-monitoring/alignak")
          self.send_an_element(make_monitoring_log(
              'warning', 'SEND_CUSTOM_HOST_NOTIFICATION: this command is not implemented!'))
docs: DOES NOTHING (Should send a custom notification)
          Format of the line that triggers function call::
  
          SEND_CUSTOM_HOST_NOTIFICATION;<host_name>;<options>;<author>;<comment>
  
          :param host: host to send notif for
          :type host: alignak.object.host.Host
          :param options: notification options
          :type options:
          :param author: notification author
          :type author: str
          :param comment: notification text
          :type comment: str
          :return: None