Take a look at the python-oauth2 project.
:
import oauth2 as oauth
consumer = oauth.Consumer(key="your-twitter-consumer-key",
secret="your-twitter-consumer-secret")
request_token_url = "http://twitter.com/oauth/request_token"
client = oauth.Client(consumer)
resp, content = client.request(request_token_url, "GET")
print resp
print content