fact: Definition prebicat_2cell_struct (C : precategory_ob_mor) : UU := ∏ (a b: C), C⟦a, b⟧ → C⟦a, b⟧ → UU.
imports: UniMath.Tactics.EnsureStructuredProofs UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.PrecategoryBinProduct