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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 get_series_as_of_date(self, series_id, as_of_date):
 """ Get latest data for a Fred series id as known on a particular date. This includes any revision to the data series before or on as_of_date, but ignores any revision on dates after as_of_date. Parameters series_id : str Fred series id such as 'GDP' as_of_date : datetime, or datetime-like str such as '10/25/2014' Include data revisions on or before this date, and ignore revisions afterwards Returns ------- data : Series a Series where each index is the observation date and the value is the data for the Fred series """

        as_of_date = pd.to_datetime(as_of_date)
        df = self.get_series_all_releases(series_id)
        data = df[df['realtime_start'] <= as_of_date]
        return data