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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _check_dataframe_localize_timestamps(pdf, timezone):
 """ 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 """

    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