def _get_version(self, oauth_request):
        """Verify the correct version request for this server."""
        try:
            version = oauth_request.get_parameter('oauth_version')
        except:
            version = VERSION
        if version and version != self.version:
            raise OAuthError('OAuth version %s not supported.' % str(version))
        return version
Verify the correct version request for this server.
twitter/oauth.py