def replication(func):
    """
    Decorator to declare which methods are accessible for different
    type of servers:

    * If option replication_server is None then this decorator
      doesn't matter.
    * If option replication_server is True then ONLY decorated with
      this decorator methods will be started.
    * If option replication_server is False then decorated with this
      decorator methods will NOT be started.

    :param func: function to mark accessible for replication
    """
    func.replication = True
    return func
