∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C] {X Y : C}
  {f : X ⟶ Y} [inst_2 : CategoryTheory.IsSplitMono f] {c : CategoryTheory.Limits.CokernelCofork f}
  (i : CategoryTheory.Limits.IsColimit c),
  CategoryTheory.CategoryStruct.comp
      (let c' := CategoryTheory.Limits.CokernelCofork.ofπ (CategoryTheory.Limits.Cofork.π c) ⋯;
      let i' := CategoryTheory.Limits.isCokernelEpiComp i (CategoryTheory.retraction f) ⋯;
      let i'' := CategoryTheory.Preadditive.isColimitCoforkOfCokernelCofork i';
      (CategoryTheory.Limits.splitEpiOfIdempotentOfIsColimitCofork C ⋯ i'').section_)
      (CategoryTheory.retraction f) =
    0