title: using python3 libs in ros kinetic
body: <p>I am working with project, connected with ROS Kinetic. I wrote my nodes, using Python3 and tried to transfer some information with ros-service from 1 node to another. This information represents a huge object that couldn't be easilly formatted to normal ROS types, so I used <code>pickle.dumps(object, 0).decode()</code> and send it like a string.In the server side I couldn't use pickle and met an exception about: <code>No module named search</code>.
  The code of the server side: </p>
  
  <pre><code>#!/usr/bin/env python3
  from visualization.srv import *
  import rospy
  import pickle
  
  megafoo = []
  
  def handle_nodes(req):
      global megafoo
      print(type(req.nodes))
      megafoo.extend(pickle.loads(req.nodes.encode()))
      print(len(megafoo))
      a=1
      print("A request type: {0}".format(type(req)))
      return ListNodesResponse(a)
  
  def nodes_creater_server():
      rospy.init_node('nodes_server')
      s = rospy.Service('draw_some_nodes', ListNodes, handle_nodes)
      print('ready to draw nodes')
      rospy.spin()
  
  if __name__ == "__main__":
      nodes_creater_server()
  </code></pre>
  
  <p>I tried to make this without calling pickle and problem was resolved so I think that I can't call pickle from server somehow</p>