∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {J : CategoryTheory.Limits.MulticospanShape}
  {I : CategoryTheory.Limits.MulticospanIndex J C} {c : CategoryTheory.Limits.Fan I.left}
  {d : CategoryTheory.Limits.Fan I.right} (hd : CategoryTheory.Limits.IsLimit d)
  (a : CategoryTheory.Limits.Fork (I.fstPiMapOfIsLimit c hd) (I.sndPiMapOfIsLimit c hd)) (i : J.R),
  (CategoryTheory.Limits.Multifork.ofPiFork a).π.app (CategoryTheory.Limits.WalkingMulticospan.right i) =
    CategoryTheory.CategoryStruct.comp a.ι (CategoryTheory.CategoryStruct.comp (I.fstPiMapOfIsLimit c hd) (d.proj i))