@abc.abstractmethod<EOL><INDENT>def copy_gradebook_column_entries(self, source_gradebook_column_id, target_gradebook_column_id):<DEDENT>
pass<EOL>
Copies gradebook column entries from one column to another.

        If the target grade column grade system differs from the source,
        the grades in the entries are transformed to the new grade
        system.

        :param source_gradebook_column_id: the ``Id`` of a ``GradebookColumn``
        :type source_gradebook_column_id: ``osid.id.Id``
        :param target_gradebook_column_id: the ``Id`` of a ``GradebookColumn``
        :type target_gradebook_column_id: ``osid.id.Id``
        :raise: ``NotFound`` -- ``source_gradebook_column_id ortarget_gradebook_column_id`` is not found
        :raise: ``NullArgument`` -- ``source_gradebook_column_id target_gradebook_column_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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