docs: def ls(self, startswith=None):
          '''
          List all cubes available to the calling client.
  
          :param startswith: string to use in a simple "startswith" query filter
          :returns list: sorted list of cube names
          '''
          logger.info('Listing cubes starting with "%s")' % startswith)
          startswith = unicode(startswith or '')
          tables = sorted(name for name in self.db_tables
                          if name.startswith(startswith))
          return tables