fact: Definition cyl_extension' {A B} (f : A -> B) (C : B -> Type) (g : forall a, C (pr_cyl (cyl a))) (ext : ExtensionAlong f C g) : ExtensionAlong cyl (C o pr_cyl) g.
imports: HoTT.Basics HoTT.Types Equiv.PathSplit PathAny Cubical.DPath Cubical.DPathSquare Colimits.Coeq Colimits.MappingCylinder