fact: Definition double_id_mor {C : category} {D : twosided_disp_cat C C} (I : hor_id_data D) {x y : C} (f : x --> y) : double_id I x -->[ f ][ f ] double_id I y := pr2 I x y f.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.TwoSidedDisplayedCats.TwoSidedDispCat UniMath.CategoryTheory.TwoSidedDisplayedCats.Isos