code: def set_max_requests_per_connection(self, host_distance, max_requests):
          
          if self.protocol_version >= 3:
              raise UnsupportedOperation(
                  "Cluster.set_max_requests_per_connection() only has an effect "
                  "when using protocol_version 1 or 2.")
          if max_requests < 1 or max_requests > 127 or \
             max_requests <= self._min_requests_per_connection[host_distance]:
              raise ValueError("max_requests must be 1-127 and greater than the min_requests for this host_distance (%d)" %
                               (self._min_requests_per_connection[host_distance],))
          self._max_requests_per_connection[host_distance] = max_requests
docs: Sets a threshold for concurrent requests per connection, above which new
          connections will be created to a host (up to max connections;
          see :meth:`~Cluster.set_max_connections_per_host`).
  
          Pertains to connection pool management in protocol versions {1,2}.