code: def test_multi_dtype(self):
      # multi-dtype
      df = DataFrame(
          [[1, 2, 1.0, 2.0, 3.0, "foo", "bar"]],
          columns=["a", "a", "b", "b", "d", "c", "c"],
      )
      df.columns = list("ABCDEFG")
      expected = DataFrame(
          [[1, 2, 1.0, 2.0, 3.0, "foo", "bar"]], columns=list("ABCDEFG")
      )
      tm.assert_frame_equal(df, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Series, date_range
  import pandas._testing
label_desc: Use image node_id 12 for calling the TestDataFrameNonuniqueIndexes obj's underlying member method code with example usage: obj.test_multi_dtype() without return types