code: def test_subclassed_melt(self):
      # GH 15564
      cheese = tm.SubclassedDataFrame(
          {
              "first": ["John", "Mary"],
              "last": ["Doe", "Bo"],
              "height": [5.5, 6.0],
              "weight": [130, 150],
          }
      )
  
      melted = pd.melt(cheese, id_vars=["first", "last"])
  
      expected = tm.SubclassedDataFrame(
          [
              ["John", "Doe", "height", 5.5],
              ["Mary", "Bo", "height", 6.0],
              ["John", "Doe", "weight", 130],
              ["Mary", "Bo", "weight", 150],
          ],
          columns=["first", "last", "variable", "value"],
      )
  
      tm.assert_frame_equal(melted, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 15 for calling the TestDataFrameSubclassing obj's underlying member method code with example usage: obj.test_subclassed_melt() without return types