could not locate runnable browser

I'm trying to open internet explorer with webbrowser, this is my simple code:

import webbrowser'
Op=webbrowser.get("iexplorer")
Op.open("www.facebook.com")'

but it returns me in error:

  

Traceback (most recent call last): File   "C: \ Users \ None \ Desktop \ Test2.pyw", line 11, in       Op = webbrowser.get ("webbrowser.iexplorer") File "C: \ Users \ None \ lib \ webbrowser.py", line 51, in get       raise Error ("could not locate runnable browser") webbrowser.Error: could not locate runnable browser

I've tried putting .exe and many other ways but none works for me