code: def included(self, start, stop):
          
          for event in self:
              if (start <= event.begin <= stop # if start is between the bonds
              and start <= event.end <= stop): # and stop is between the bonds
                  yield event
docs: Iterates (in chronological order) over every event that is included
          in the timespan between `start` and `stop`
  
          Args:
              start : (Arrow object)
              stop : (Arrow object)