code: def recv_downstream(self, flags=0, timeout=2000.0):
      # wait for a message, so we won't block if there was a bug
      self.downstream_poller.poll(timeout)
  
      msg = self.downstream.recv_multipart(flags)
      return self.deserialize(msg)
  
imports: import re
  import socket
  from functools import reduce
  import zmq
  from ipyparallel.serialize import deserialize_object, serialize_object
  from ipyparallel.util import disambiguate_url
label_desc: Use image node_id 10 for calling the BinaryTreeCommunicator obj's underlying member method code with example usage: obj.recv_downstream(flags, timeout) and returns: self