∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] [inst_1 : CategoryTheory.Abelian C]
  (S : CategoryTheory.ShortComplex.SnakeInput C),
  CategoryTheory.CategoryStruct.comp S.L₀X₂ToP (CategoryTheory.Limits.pullback.snd S.L₁.g S.v₀₁.τ₃) = S.L₀.g