code: def test_mangles_multi_index(all_parsers, data, expected):
      # see gh-18062
      parser = all_parsers
  
      result = parser.read_csv(StringIO(data), header=[0, 1])
      tm.assert_frame_equal(result, expected)
  
imports: from collections import namedtuple
  from io import StringIO
  import numpy
  import pytest
  from pandas.errors import ParserError
  from pandas import DataFrame, Index, MultiIndex
  import pandas._testing
label_desc: Use image node_id 21 for calling a global function with example usage: test_mangles_multi_index(all_parsers, data, expected) without return types