@abc.abstractmethod<EOL><INDENT>def get_offset_events(self):<DEDENT>
return<EOL>
Gets all ``OffsetEvents``.

        :return: an ``OffsetEventList``
        :rtype: ``osid.calendaring.OffsetEventList``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*