@abc.abstractmethod<EOL><INDENT>def get_fixed_start_offset(self):<DEDENT>
return<EOL>
Gets the fixed starting time offset.

        :return: the offset
        :rtype: ``osid.calendaring.Duration``
        :raise: ``IllegalState`` -- ``has_fixed_start_offset()`` is ``false``

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