pub(crate) fn apply_transform<F>(transform: F, tree: &T, meta: &M) -> Option<Self>

    where

        F: Fn(&mut Commands<T, M>, &T, &M) -> Option<T>,

    {

        let mut commands = Commands::new();

        let new_tree = transform(&mut commands, &tree, &meta)?;

        Some(Self { new_tree, commands })

    }