code: from pandas import Index
  import pandas.testing as tm
  
  
  def test_astype_str_from_bytes():
      # https://github.com/pandas-dev/pandas/issues/38607
      idx = Index(["あ", b"a"], dtype="object")
      result = idx.astype(str)
      expected = Index(["あ", "a"], dtype="object")
      tm.assert_index_equal(result, expected)
  