code: def test_mixed_depth_pop(self):
      arrays = [
          ["a", "top", "top", "routine1", "routine1", "routine2"],
          ["", "OD", "OD", "result1", "result2", "result1"],
          ["", "wx", "wy", "", "", ""],
      ]
  
      tuples = sorted(zip(*arrays))
      index = MultiIndex.from_tuples(tuples)
      df = DataFrame(
          np.random.default_rng(2).standard_normal((4, 6)),
          columns=index,
      )
  
      df1 = df.copy()
      df2 = df.copy()
      result = df1.pop("a")
      expected = df2.pop(("a", "", ""))
      tm.assert_series_equal(expected, result, check_names=False)
      tm.assert_frame_equal(df1, df2)
      assert result.name == "a"
  
      expected = df1["top"]
      df1 = df1.drop(["top"], axis=1)
      result = df2.pop("top")
      tm.assert_frame_equal(expected, result)
      tm.assert_frame_equal(df1, df2)
  
imports: import numpy
  from pandas import DataFrame, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 3 for calling the TestDataFramePop obj's underlying member method code with example usage: obj.test_mixed_depth_pop() without return types