fact: Definition extendable_compose (n : nat) {A B C : Type} (P : C -> Type) (f : A -> B) (g : B -> C) : ExtendableAlong n g P -> ExtendableAlong n f (fun b => P (g b)) -> ExtendableAlong n (g o f) P.
imports: HoTT.Basics HoTT.Types Equiv.PathSplit PathAny Cubical.DPath Cubical.DPathSquare Colimits.Coeq Colimits.MappingCylinder