code: def _check_dataframe_localize_timestamps(pdf, timezone):
      
      from pyspark.sql.utils import require_minimum_pandas_version
      require_minimum_pandas_version()
  
      for column, series in pdf.iteritems():
          pdf[column] = _check_series_localize_timestamps(series, timezone)
      return pdf
docs: Convert timezone aware timestamps to timezone-naive in the specified timezone or local timezone
  
      :param pdf: pandas.DataFrame
      :param timezone: the timezone to convert. if None then use local timezone
      :return pandas.DataFrame where any timezone aware columns have been converted to tz-naive