∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] [inst_1 : CategoryTheory.MonoidalCategory C]
  {A B : CategoryTheory.Mon C} {M N : Bimod A B} (self : M.Hom N),
  CategoryTheory.CategoryStruct.comp M.actLeft self.hom =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.MonoidalCategoryStruct.whiskerLeft A.X self.hom) N.actLeft