code: def to_json(self):
          
          return {
              'st_month': self.st_month,
              'st_day': self.st_day,
              'st_hour': self.st_hour,
              'end_month': self.end_month,
              'end_day': self.end_day,
              'end_hour': self.end_hour,
              'timestep': self.timestep,
              'is_leap_year': self.is_leap_year
          }
docs: Convert the analysis period to a dictionary.