add a parameter to the query string of a URL. is this really the easiest way to do this (without resorting to a non-standard library)?

add_param_to_url.py

import urlparse                                             
import urllib                                               

def add_param_to_url(url, param, val):                      
  parsed = urlparse.urlsplit(url)._asdict()                 
  query = urlparse.parse_qs(parsed['query'])                
  query[param] = [val]                                      
  parsed['query'] = urllib.urlencode(query, True)           
  return urlparse.urlunsplit(urlparse.SplitResult(**parsed))

if __name__ == '__main__':                                  
  import sys                                                
  print add_param_to_url(*sys.argv[1:])