fact: Definition nat_trans_total_category_of_set_functor_is_nat_trans : is_nat_trans _ _ nat_trans_total_category_of_set_functor_data.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Univalence UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Setcategories UniMath.CategoryTheory.whiskering UniMath.CategoryTheory.Categories.CategoryOfSetCategories UniMath.CategoryTheory.GrothendieckConstruction.TotalCategory