code: def test_keys(self):
      pdf = pd.DataFrame(
          [[1, 2], [4, 5], [7, 8]],
          index=["cobra", "viper", "sidewinder"],
          columns=["max_speed", "shield"],
      )
      psdf = ps.from_pandas(pdf)
  
      self.assert_eq(psdf.keys(), pdf.keys())
  
imports: import unittest
  import numpy
  import pandas
  from pyspark import pandas
  from pyspark.pandas.config import option_context
  from pyspark.testing.pandasutils import ComparisonTestBase
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 5 for calling the FrameIndexingMixin obj's underlying member method code with example usage: obj.test_keys() without return types