code: def test_melt_mixed_int_str_id_vars(self):
      # GH 29718
      df = DataFrame({0: ["foo"], "a": ["bar"], "b": [1], "d": [2]})
      result = melt(df, id_vars=[0, "a"], value_vars=["b", "d"])
      expected = DataFrame(
          {
              0: ["foo"] * 2,
              "a": ["bar"] * 2,
              "variable": list("bd"),
              "value": [1, 2],
          }
      )
      tm.assert_frame_equal(result, expected)
  
imports: import re
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, date_range, lreshape, melt, wide_to_long
  import pandas._testing
label_desc: Use image node_id 17 for calling the TestMelt obj's underlying member method code with example usage: obj.test_melt_mixed_int_str_id_vars() without return types