∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Limits.HasZeroMorphisms C]
  {K : ChainComplex C ℕ} {L : CochainComplex C ℕ} [inst_2 : SizeOf C] (d₀ : K.X 0 ⟶ L.X 0)
  (comp_d₀ : CategoryTheory.CategoryStruct.comp (K.d 1 0) d₀ = 0)
  (d₀_comp : CategoryTheory.CategoryStruct.comp d₀ (L.d 0 1) = 0),
  sizeOf { d₀ := d₀, comp_d₀ := comp_d₀, d₀_comp := d₀_comp } = 1 + sizeOf d₀ + sizeOf comp_d₀ + sizeOf d₀_comp