Unable to debug on Raspberry Pi using python tools

Question

I've been trying to debug a python code on my RPi from VS2013 using python tools for visual studio, but failed all the time to connect to the python console running in Pi,

this is my code frag.in Pi:

import ptvsd
ptvsd.enable_attach('secret',address = ('0.0.0.0',5678))
ptvsd.wait_for_attach()

for i in range(10):
    print (i)
print ('hello visual studio')

Im using Python3 in both the machines and using the latest version of ptvsd i belive (PTVS 2.1 RC2 VS 2013)

When i try to connect, I'm getting an error message which says

Remote server at tcp://secret@rgpi:5678/ is not a Python tools for Visual Studio remote debugging server, or it's version is not supported.

where rgpi is the hostname of my Pi, any help would be much appreciated, thanks