code: def _verify_connection(self):
          
          try:
              res = self._session.get(self._connection_validation_url, json={})
              logger.debug(consts.LOG_MSG_VERIFYING_CONNECTION,
                           self._connection_validation_url,
                           res if res else 'No result from backend')
              if not res.ok:
                  raise requests.exceptions.RequestException(res.content)
              remote_batch_size = res.json().get(consts.MAX_REQUEST_SIZE_FIELD,
                                                 consts.DEFAULT_BATCH_SIZE)
              if remote_batch_size < self._batch_max_size:
                  self._batch_max_size = remote_batch_size
                  self._notify(logging.INFO,
                               consts.LOG_MSG_NEW_BATCH_SIZE % remote_batch_size)
              self._is_connected.set()
              return True
  
          except requests.exceptions.RequestException as ex:
              msg = consts.LOG_MSG_CONNECTION_FAILED % str(ex)
              self._notify(logging.ERROR, msg)
              raise exceptions.ConnectionFailed(msg)
docs: Checks availability of the Alooma server
          :return: If the server is reachable, returns True
          :raises: If connection fails, raises exceptions.ConnectionFailed