@abc.abstractmethod<EOL><INDENT>def get_commitments(self):<DEDENT>
return<EOL>
Gets all commitments.

        :return: list of commitments
        :rtype: ``osid.calendaring.CommitmentList``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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