`{Funext} {A B : Type} (f : A -> B) `{O_inverts f} (Z : Type) `{In O Z} : IsEquiv (fun g:B->Z => g o f). Proof. srapply (equiv_extendable_isequiv 0). exact (ooextendable_O_inverts f Z 2). Defined.
Require Import HoTT.Basics HoTT.Types. Require Import Equiv.BiInv Extensions HProp HFiber NullHomotopy Limits.Pullback. Require Import Homotopy.IdentitySystems. Require Import Colimits.Pushout.