ROSCONSOLE_FORMAT not working in ROSPY on Hydro

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I tried to use ROSCONSOLE_FORMAT as shown in Console Output Formatting on rosconsole wiki.

I configured my .bashrc as shown below:

source /opt/ros/hydro/setup.bash 
source ~/myproject/devel/setup.bash
export ROS_HOSTNAME=localhost
export ROS_MASTER_URI=<removed_link>
export ROBOT=sim
export ROSCONSOLE_FORMAT='[${severity}] [${node}@${function}:${line}]: ${message}'

For C++ I get expected outputs. However for any python program, for example

#!/usr/bin/env python
# license removed for brevity
import rospy
from std_msgs.msg import String

def talker():
    # pub = rospy.Publisher('chatter', String, queue_size=10)
    rospy.init_node('talker', anonymous=True)
    r = rospy.Rate(1)  # 10hz
    while not rospy.is_shutdown():
        # str = "hello world %s" % rospy.get_time()
        rospy.loginfo("Hello World!")
        # pub.publish(str)
        r.sleep()

if __name__ == '__main__':
    try:
        talker()
    except rospy.ROSInterruptException:
        pass

I get unformatted outputs like:

mjyc@ubuntu:~$ python test.py
[INFO] [WallTime: 1405812621.854884] Hello World!
[INFO] [WallTime: 1405812622.856649] Hello World!
[INFO] [WallTime: 1405812623.856340] Hello World!
[INFO] [WallTime: 1405812624.856789] Hello World!
[INFO] [WallTime: 1405812625.855262] Hello World!

Anybody has any clue?

I'm on Ubuntu 12.04 and using hydro.