∀ {C : Type u_1} [inst : CategoryTheory.Category.{u_3, u_1} C] {D : Type u_2}
  [inst_1 : CategoryTheory.Category.{u_4, u_2} D] (F : CategoryTheory.Functor C D) (a b : C),
  Subsingleton ((⟦a⟧ ⟶ ⟦b⟧) → (Quotient.map F.obj ⋯ ⟦a⟧ ⟶ Quotient.map F.obj ⋯ ⟦b⟧))