Section contents.
Variable m: Monoid.
Variable X: Set.
Definition pick (l: ne_list.L X): MonoidMonadTrans.M m ne_tree_monad.ext X
:= lift (MonoidMonadTrans.T m) ne_tree_monad.ext X (ne_tree_monad.pick l).

Lemma pick_toLower:
ext_eq pick (@ne_tree_monad.pick _ ∘ ne_list.map (pair (monoid_zero m))).