code: def register_calendar_type(self, name, calendar_type, force=False):
          
          if force:
              self.deregister_calendar(name)
  
          if self.has_calendar(name):
              raise CalendarNameCollision(calendar_name=name)
  
          self._calendar_factories[name] = calendar_type
docs: Registers a calendar by type.
  
          This is useful for registering a new calendar to be lazily instantiated
          at some future point in time.
  
          Parameters
          ----------
          name: str
              The key with which to register this calendar.
          calendar_type: type
              The type of the calendar to register.
          force : bool, optional
              If True, old calendars will be overwritten on a name collision.
              If False, name collisions will raise an exception.
              Default is False.
  
          Raises
          ------
          CalendarNameCollision
              If a calendar is already registered with the given calendar's name.