fact: Definition op_indexed_cat : indexed_cat C.
imports: 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.OppositeCategory.Core UniMath.CategoryTheory.opp_precat UniMath.CategoryTheory.IndexedCategories.IndexedCategory