code: def test_keys(self, float_frame):
      assert float_frame.keys() is float_frame.columns
  
imports: import datetime
  import numpy
  import pytest
  from pandas.compat import IS64, is_platform_windows
  from pandas import Categorical, DataFrame, Series, date_range
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestIteration obj's underlying member method code with example usage: obj.test_keys(float_frame) without return types