{C₁ : Type u₁} →
  {C₂ : Type u₂} →
    {C₃ : Type u₃} →
      [inst : CategoryTheory.Category.{v₁, u₁} C₁] →
        [inst_1 : CategoryTheory.Category.{v₂, u₂} C₂] →
          [inst_2 : CategoryTheory.Category.{v₃, u₃} C₃] →
            {F : CategoryTheory.Functor C₁ (CategoryTheory.Functor C₂ C₃)} →
              {f₁ : CategoryTheory.Arrow C₁} →
                {f₂ f₂' : CategoryTheory.Arrow C₂} →
                  (sq₁₂ : F.PushoutObjObj f₁.hom f₂.hom) →
                    (sq₁₂' : F.PushoutObjObj f₁.hom f₂'.hom) →
                      (f₂ ≅ f₂') → (CategoryTheory.Arrow.mk sq₁₂.ι ≅ CategoryTheory.Arrow.mk sq₁₂'.ι)