code: def set_session(s):
      
  
      try:
          conn = get_connection()
      except CQLEngineException:
          # no default connection set; initalize one
          register_connection('default', session=s, default=True)
          conn = get_connection()
  
      if conn.session:
          log.warning("configuring new default connection for cqlengine when one was already set")
  
      if s.row_factory is not dict_factory:
          raise CQLEngineException("Failed to initialize: 'Session.row_factory' must be 'dict_factory'.")
      conn.session = s
      conn.cluster = s.cluster
  
      # Set default keyspace from given session's keyspace
      if conn.session.keyspace:
          from cassandra.cqlengine import models
          models.DEFAULT_KEYSPACE = conn.session.keyspace
  
      conn.setup_session()
  
      log.debug("cqlengine default connection initialized with %s", s)
docs: Configures the default connection with a preexisting :class:`cassandra.cluster.Session`
  
      Note: the mapper presently requires a Session :attr:`~.row_factory` set to ``dict_factory``.
      This may be relaxed in the future