code: def rank(self):
          
          rank = ctypes.c_int()
          check_call(_LIB.MXKVStoreGetRank(self.handle, ctypes.byref(rank)))
          return rank.value
docs: Returns the rank of this worker node.
  
          Returns
          -------
          rank : int
              The rank of this node, which is in range [0, num_workers())