content: import pytest
  
  from pandas import Index, MultiIndex, Series
  import pandas._testing as tm
  
  
  class TestSeriesRenameAxis:
      def test_rename_axis_mapper(self):
          # GH 19978
          mi = MultiIndex.from_product([["a", "b", "c"], [1, 2]], names=["ll", "nn"])
          ser = Series(list(range(len(mi))), index=mi)
  
          result = ser.rename_axis(index={"ll": "foo"})
          assert result.index.names == ["foo", "nn"]
  
          result = ser.rename_axis(index=str.upper, axis=0)
          assert result.index.names == ["LL", "NN"]
  
          result = ser.rename_axis(index=["foo", "goo"])
          assert result.index.names == ["foo", "goo"]
  
          with pytest.raises(TypeError, match="unexpected"):
              ser.rename_axis(columns="wrong")
  
      def test_rename_axis_inplace(self, datetime_series):
          # GH 15704
          expected = datetime_series.rename_axis("foo")
          result = datetime_series
          no_return = result.rename_axis("foo", inplace=True)
  
          assert no_return is None
          tm.assert_series_equal(result, expected)
  
      @pytest.mark.parametrize("kwargs", [{"mapper": None}, {"index": None}, {}])
      def test_rename_axis_none(self, kwargs):
          # GH 25034
          index = Index(list("abc"), name="foo")
          ser = Series([1, 2, 3], index=index)
  
          result = ser.rename_axis(**kwargs)
          expected_index = index.rename(None) if kwargs else index
          expected = Series([1, 2, 3], index=expected_index)
          tm.assert_series_equal(result, expected)
  