docs: def scan(self, match="*", count=1000, cursor=0):
          """ Iterates the set of keys in :prop:key_prefix in :prop:_client
              @match: #str pattern to match after the :prop:key_prefix
              @count: the user specified the amount of work that should be done
                  at every call in order to retrieve elements from the collection
              @cursor: the next cursor position
  
              -> #tuple (#int cursor position in scan, #list of full key names)
          """
          cursor, data = self._client.scan(
              cursor=cursor,
              match="{}:{}".format(self.key_prefix, match),
              count=count)
          return (cursor, list(map(self._decode, data)))