Python Pika callback is not working with SelectConnection inside a class -

i trying create simple python pika selectconnection , seems not able open connection using on_open_callback , don't te on_open_error_callback either. can suggest might causing problem?

import pika  class rabbitmqtransport(object):      def __init__(self):          self._connection = none         self._channel = none         self._connect()      def on_connection_open(self):         print "connection created"      def on_connection_open_error(self):         print "connection open error"      def _connect(self):         # setup rabbitmq connection         credentials = pika.plaincredentials('guest','guest')         parameters = pika.urlparameters('amqp://guest:guest@localhost:5672/%2f')           print "creating connection"         self._connection = pika.selectconnection(parameters=parameters,on_open_callback=self.on_connection_open,on_open_error_callback=self.on_connection_open_error)         print self._connection.connection_state         print dir(self._connection)         print self._connection.is_open  r = rabbitmqtransport() 

found problem, added line bellow , connection opened , callback worked.

self._connection.ioloop.start()