Gets the repository administrative session for creating,
        updating and deleteing repositories.

        return: (osid.repository.RepositoryAdminSession) - a
                RepositoryAdminSession
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - supports_repository_admin() is false
        compliance: optional - This method must be implemented if
                    supports_repository_admin() is true.

def get_repository_admin_session(self):
        """Gets the repository administrative session for creating,
        updating and deleteing repositories.

        return: (osid.repository.RepositoryAdminSession) - a
                RepositoryAdminSession
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - supports_repository_admin() is false
        compliance: optional - This method must be implemented if
                    supports_repository_admin() is true.

        """
        if not self.supports_repository_admin():
            raise Unimplemented()
        try:
            from . import sessions
        except ImportError:
            raise  # OperationFailed()
        try:
            session = sessions.RepositoryAdminSession(proxy=self._proxy,
                                                      runtime=self._runtime)
        except AttributeError:
            raise  # OperationFailed()
        return session