'Registers a calendar for retrieval by the get_calendar method.
Parameters
name: str
The key with which to register this calendar.
calendar: TradingCalendar
The calendar to be registered for retrieval.
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.'

def register_calendar(self, name, calendar, force=False):

    if force:
        self.deregister_calendar(name)
    if self.has_calendar(name):
        raise CalendarNameCollision(calendar_name=name)
    self._calendars[name] = calendar
