∀ {J : Type v} [inst : CategoryTheory.SmallCategory J] (F : CategoryTheory.Functor J MonCat)
  [inst_1 : CategoryTheory.IsFiltered J],
  MonCat.FilteredColimits.colimitOne F = { one := MonCat.FilteredColimits.M.mk F ⟨⋯.some, 1⟩ }