(K : Type u_1) →
  [inst : Field K] →
    [inst_1 : NumberField K] →
      (I : FractionalIdeal (nonZeroDivisors (NumberField.RingOfIntegers K)) K) →
        Module.Basis (Module.Free.ChooseBasisIndex ℤ ↥↑I) ℤ ↥↑I