∀ {K : Type u_1} [inst : Field K] [inst_1 : NumberField K]
  {u : Fin (NumberField.Units.rank K) → (NumberField.RingOfIntegers K)ˣ} (hu : NumberField.Units.IsMaxRank u),
  NumberField.Units.basisOfIsMaxRank hu =
    (basisOfPiSpaceOfLinearIndependent ⋯).reindex (NumberField.Units.equivFinRank K).symm