<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_root_log(self, log_id):
 """Adds a root log. arg: log_id (osid.id.Id):
 the ``Id`` of a log raise: AlreadyExists - ``log_id`` is already in hierarchy raise: NotFound - ``log_id`` is not found raise: NullArgument - ``log_id`` is ``null`` raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure *compliance: mandatory -- This method must be implemented.* """

        # Implemented from template for
        # osid.resource.BinHierarchyDesignSession.add_root_bin_template
        if self._catalog_session is not None:
            return self._catalog_session.add_root_catalog(catalog_id=log_id)
        return self._hierarchy_session.add_root(id_=log_id)