∀ {R : Type u} [inst : CommRing R] {M N P Q : ModuleCat R} (f : ↑M →ₗ[R] ↑N →ₗ[R] ↑P) (g : ↑P →ₗ[R] ↑Q),
  ModuleCat.ofHom₂ (f.compr₂ g) =
    CategoryTheory.CategoryStruct.comp (ModuleCat.ofHom₂ f)
      (ModuleCat.ofHom (CategoryTheory.Linear.rightComp R N (ModuleCat.ofHom g)))