{C : Type u} →
  [inst : CategoryTheory.Category.{v, u} C] →
    [inst_1 : CategoryTheory.Preadditive C] →
      [inst_2 : CategoryTheory.Limits.HasBinaryBiproducts C] →
        {X₁ X₂ Y₁ Y₂ : C} → (X₁ ⟶ Y₁) → (X₁ ⟶ Y₂) → (X₂ ⟶ Y₁) → (X₂ ⟶ Y₂) → (X₁ ⊞ X₂ ⟶ Y₁ ⊞ Y₂)