Function action_node 

pub fn action_node(
    base: &TreePath,
    app: &str,
    resource_kind: &str,
    resource: &str,
    field: Option<&str>,
    action: &str,
) -> TreePath

The node of the action action on the resource resource (of kind resource_kind) the app app publishes, below base (a room, or the root for a path relative to one), and below the one field it writes if any: where every door decides it.