code: def minutes_count_for_sessions_in_range(self, start_session, end_session):
          
          return int(self._minutes_per_session[start_session:end_session].sum())
docs: Parameters
          ----------
          start_session: pd.Timestamp
              The first session.
  
          end_session: pd.Timestamp
              The last session.
  
          Returns
          -------
          int: The total number of minutes for the contiguous chunk of sessions.
               between start_session and end_session, inclusive.