@abc.abstractmethod<EOL><INDENT>def has_assessment_begun(self, assessment_taken_id):<DEDENT>
return<EOL>
Tests if this assessment has started.

        An assessment begins from the designated start time if a start
        time is defined. If no start time is defined the assessment may
        begin at any time. Assessment sections cannot be accessed if the
        return for this method is ``false``.

        :param assessment_taken_id: ``Id`` of the ``AssessmentTaken``
        :type assessment_taken_id: ``osid.id.Id``
        :return: ``true`` if this assessment has begun, ``false`` otherwise
        :rtype: ``boolean``
        :raise: ``NotFound`` -- ``assessment_taken_id`` is not found
        :raise: ``NullArgument`` -- ``assessment_taken_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure occurred

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