{C : Type u} →
  [inst : CategoryTheory.Category.{v, u} C] →
    {F : CategoryTheory.Functor CategoryTheory.Limits.WalkingSpan C} →
      (t : CategoryTheory.Limits.Cocone F) →
        (CategoryTheory.Limits.Cocones.precompose (CategoryTheory.Limits.diagramIsoSpan F).inv).obj t ≅
          CategoryTheory.Limits.PushoutCocone.mk (t.ι.app CategoryTheory.Limits.WalkingSpan.left)
            (t.ι.app CategoryTheory.Limits.WalkingSpan.right) ⋯