∀ (C : Type u_1) {ι : Type u_2} [inst : CategoryTheory.Category.{v_1, u_1} C] [inst_1 : CategoryTheory.Preadditive C]
  {c : ComplexShape ι} (i j : ι) [inst_2 : CategoryTheory.CategoryWithHomology C] (K : HomologicalComplex C c),
  (HomologicalComplex.HomologySequence.composableArrows₃Functor C i j).obj K =
    HomologicalComplex.HomologySequence.composableArrows₃ K i j