<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def list_backups(self, limit=20, marker=0):
 """ Returns a paginated list of backups for this instance. """

        return self.manager._list_backups_for_instance(self, limit=limit,
                                                       marker=marker)