docs: def setup_cassandra(self, namespaces):
      """
      Set up a connection to the specified Cassandra cluster and create the
      specified keyspaces if they dont exist.
      """
      connections_to_shutdown = []
      self.cluster = Cluster(self.hosts)
  
      for namespace_name in namespaces:
        keyspace = '%s_%s' % (self.keyspace_prefix, namespace_name)
        namespace = Namespace(self.cluster, keyspace,
                              self.replication_factor, self.read_size)
        connections_to_shutdown.append(namespace.session)
        self.namespaces[namespace_name] = namespace
  
      # Shutdown Cluster instance after shutting down all Sessions.
      connections_to_shutdown.append(self.cluster)
  
      # Shutdown all connections to Cassandra before exiting Python interpretter.
      atexit.register(lambda: map(lambda c: c.shutdown(),
                                  connections_to_shutdown))