code: def test_mangle_dupe_cols_already_exists_unnamed_col(all_parsers):
      # GH#14704
      parser = all_parsers
  
      data = ",Unnamed: 0,,Unnamed: 2\n1,2,3,4"
      result = parser.read_csv(StringIO(data))
      expected = DataFrame(
          [[1, 2, 3, 4]],
          columns=[
              "Unnamed: 0.1",
              "Unnamed: 0",
              "Unnamed: 2.1",
              "Unnamed: 2",
          ],
      )
      tm.assert_frame_equal(result, expected)
  
file_path: pandas/pandas/tests/io/parser/test_mangle_dupes.py
imports: from io import StringIO
  import pytest
  from pandas import DataFrame
  import pandas._testing
label_desc: Use image node_id 8 for calling a global function with example usage: test_mangle_dupe_cols_already_exists_unnamed_col(all_parsers) without return types