proposition: Lemma is_invertible_2cell_lunitor {a b : C} (f : C ⟦ a, b ⟧) : is_invertible_2cell (lunitor f).
proof: Proof. exists (linvunitor f). abstract (apply (lunitor_linvunitor _ ,, linvunitor_lunitor _)). Defined.
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