code: def build_tree(self, rebuild=False):
          
  
          time_qualifier = self.process_hierarchy.bottom_process.time_qualifier
          process_name = self.process_hierarchy.bottom_process.process_name
          if rebuild or self.build_timeperiod is None:
              timeperiod = settings.settings['synergy_start_timeperiod']
          else:
              timeperiod = self.build_timeperiod
  
          timeperiod = cast_to_time_qualifier(time_qualifier, timeperiod)
          actual_timeperiod = time_helper.actual_timeperiod(time_qualifier)
  
          while actual_timeperiod >= timeperiod:
              self.get_node(process_name, timeperiod)
              timeperiod = time_helper.increment_timeperiod(time_qualifier, timeperiod)
  
          self.build_timeperiod = actual_timeperiod
docs: method builds tree by iterating from the synergy_start_timeperiod to the current time
              and inserting corresponding nodes