∀ {J : Type u_8} [inst : CategoryTheory.Category.{u_7, u_8} J] {K : Type u_4}
  [inst_1 : CategoryTheory.Category.{u_3, u_4} K] {C : Type u_6} [inst_2 : CategoryTheory.Category.{u_5, u_6} C]
  {D : Type u_2} [inst_3 : CategoryTheory.Category.{u_1, u_2} D] (H : CategoryTheory.Functor C D)
  {F : CategoryTheory.Functor J C} {E : CategoryTheory.Functor K J} {c : CategoryTheory.Limits.Cone F} (j : K),
  (H.mapCone (CategoryTheory.Limits.Cone.whisker E c)).π.app j =
    CategoryTheory.CategoryStruct.comp
      (CategoryTheory.Iso.refl (H.mapCone (CategoryTheory.Limits.Cone.whisker E c)).pt).hom
      ((CategoryTheory.Limits.Cone.whisker E (H.mapCone c)).π.app j)