@staticmethod
def interface_roles_dont_change_and_tree_transitions_from_active_to_unsure_and_best_upstream_neighbor_is_not_null(
    interface: 'TreeInterfaceDownstream'):
    """
        Tree transitions from Active to Unsure state AND
        BestUpstream neighbor is not null
        """
    interface.logger.debug(
        'interface_roles_dont_change_and_tree_transitions_from_active_to_unsure_and_best_upstream_neighbor_is_not_null'
        )
    interface.send_i_am_no_longer_upstream()
    interface.send_no_interest()
