∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Preadditive C]
  {F G : CochainComplex C ℤ} {n : ℤ} (γ : CochainComplex.HomComplex.Cochain F G n) (p q q' : ℤ) (hpq : p + n = q)
  (hq' : q = q'), CategoryTheory.CategoryStruct.comp (γ.v p q hpq) (HomologicalComplex.XIsoOfEq G hq').hom = γ.v p q' ⋯