∀ (M : Type u_1) [inst : AddMonoid M] {X₁ Y₁ Z₁ X₂ Y₂ Z₂ : CategoryTheory.Discrete M} (f₁ : X₁ ⟶ Y₁) (f₂ : X₂ ⟶ Y₂)
  (g₁ : Y₁ ⟶ Z₁) (g₂ : Y₂ ⟶ Z₂),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom ⋯) (CategoryTheory.eqToHom ⋯) = CategoryTheory.eqToHom ⋯