@classmethod
def delete_event(cls, event, form):
    """Deletes ``event``, syncing changes to Google Calendar.

        Calls either :func:`delete_series`, :func:`delete_single_event`, or
        :func:`delete_single_event_from_series` depending on whether the
        event is recurring and whether all updates in a series should be
        deleted.

        :param event: The event to delete.
        :type event: :class:`Event`
        :param form: The WTForms form that specifies whether or not all events
            in a series should be deleted, or just a single event.
        :type form: :class:`DeleteEventForm`.

        :raises: :class:`GoogleCalendarAPIError` and it's subclasses

        :returns: Response from the Google Calendar API.
        :rtype: dict
        """
    if event.is_recurring:
        if form.delete_all.data:
            return cls.delete_series(event)
        return cls.delete_single_event_from_series(event)
    return cls.delete_single_event(event)
