fact: Definition three_ob0 {C : category} (xyz : three C) : C := pr111 xyz.
imports: UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Prelude UniMath.CategoryTheory.PrecategoryBinProduct UniMath.CategoryTheory.DisplayedCats.Core UniMath.CategoryTheory.DisplayedCats.Total UniMath.CategoryTheory.Limits.Graphs.Colimits UniMath.CategoryTheory.DisplayedCats.Examples.Arrow