code: def test_duplicate_columns(self):
      # https://github.com/wesm/feather/issues/53
      # not currently able to handle duplicate columns
      df = pd.DataFrame(
          np.arange(12).reshape(4, 3), columns=list("aaa")
      ).copy()
      self.check_external_error_on_write(df)
  
imports: import numpy
  import pytest
  import pandas
  import pandas._testing
  from pandas.core.arrays import ArrowStringArray, StringArray
  from pandas.io.feather_format import read_feather, to_feather
label_desc: Use image node_id 6 for calling the TestFeather obj's underlying member method code with example usage: obj.test_duplicate_columns() without return types