∀ (C : Type u_2) [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C]
  (T : CategoryTheory.Monad C) [inst_2 : T.Additive] (P Q R : T.Algebra) (f f' : P ⟶ Q) (g : Q ⟶ R),
  CategoryTheory.CategoryStruct.comp (f + f') g =
    CategoryTheory.CategoryStruct.comp f g + CategoryTheory.CategoryStruct.comp f' g