∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] {W : CategoryTheory.MorphismProperty C}
  [inst_1 : W.HasLeftCalculusOfFractions] {E : Type u_3} [inst_2 : CategoryTheory.Category.{v_3, u_3} E]
  (F₁ F₂ : CategoryTheory.Functor (CategoryTheory.MorphismProperty.LeftFraction.Localization W) E),
  (CategoryTheory.MorphismProperty.LeftFraction.Localization.Q W).comp F₁ =
      (CategoryTheory.MorphismProperty.LeftFraction.Localization.Q W).comp F₂ →
    F₁ = F₂