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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 load_tree(self):
 """ method iterates thru all objects older than synergy_start_timeperiod parameter in job collections and loads them into this timetable"""

        timeperiod = settings.settings['synergy_start_timeperiod']
        yearly_timeperiod = time_helper.cast_to_time_qualifier(QUALIFIER_YEARLY, timeperiod)
        monthly_timeperiod = time_helper.cast_to_time_qualifier(QUALIFIER_MONTHLY, timeperiod)
        daily_timeperiod = time_helper.cast_to_time_qualifier(QUALIFIER_DAILY, timeperiod)
        hourly_timeperiod = time_helper.cast_to_time_qualifier(QUALIFIER_HOURLY, timeperiod)

        self._build_tree_by_level(QUALIFIER_HOURLY, COLLECTION_JOB_HOURLY, since=hourly_timeperiod)
        self._build_tree_by_level(QUALIFIER_DAILY, COLLECTION_JOB_DAILY, since=daily_timeperiod)
        self._build_tree_by_level(QUALIFIER_MONTHLY, COLLECTION_JOB_MONTHLY, since=monthly_timeperiod)
        self._build_tree_by_level(QUALIFIER_YEARLY, COLLECTION_JOB_YEARLY, since=yearly_timeperiod)