docs: def get_docker_memory(self, container_id, all_stats):
          """Return the container MEMORY.
  
          Input: id is the full container id
                 all_stats is the output of the stats method of the Docker API
          Output: a dict {'rss': 1015808, 'cache': 356352,  'usage': ..., 'max_usage': ...}
          """
          ret = {}
          # Read the stats
          try:
              # Do not exist anymore with Docker 1.11 (issue #848)
              # ret['rss'] = all_stats['memory_stats']['stats']['rss']
              # ret['cache'] = all_stats['memory_stats']['stats']['cache']
              ret['usage'] = all_stats['memory_stats']['usage']
              ret['limit'] = all_stats['memory_stats']['limit']
              ret['max_usage'] = all_stats['memory_stats']['max_usage']
          except (KeyError, TypeError) as e:
              # all_stats do not have MEM information
              logger.debug("docker plugin - Cannot grab MEM usage for container {} ({})".format(container_id, e))
              logger.debug(all_stats)
          # Return the stats
          return ret