fact: Definition isequiv_ooextendable `{Funext} {A B : Type} (C : B -> Type) (f : A -> B) : ooExtendableAlong f C -> IsEquiv (fun g => g oD f) := fun ps => isequiv_extendable 0 (fst (ps 1%nat), snd (ps 2)).
imports: HoTT.Basics HoTT.Types Equiv.PathSplit PathAny Cubical.DPath Cubical.DPathSquare Colimits.Coeq Colimits.MappingCylinder