∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_3, u_2} C] [inst_1 : CategoryTheory.Abelian C]
  {K L : CochainComplex C ℤ} (f : K ⟶ L) (hK : HomologicalComplex.Acyclic K) [inst_2 : L.IsKInjective],
  CochainComplex.IsKInjective.homotopyZero f hK = ⋯.some