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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 _dt_to_epoch_ns(dt_series):
 """Convert a timeseries into an Int64Index of nanoseconds since the epoch. Parameters dt_series : pd.Series The timeseries to convert. Returns ------- idx : pd.Int64Index The index converted to nanoseconds since the epoch. """

    index = pd.to_datetime(dt_series.values)
    if index.tzinfo is None:
        index = index.tz_localize('UTC')
    else:
        index = index.tz_convert('UTC')
    return index.view(np.int64)