def _proto_relative_url(self, url, scheme=None):
    if (url is None):
        return url
    if url.startswith('//'):
        if (scheme is None):
            scheme = self.http_scheme()
        return (scheme + url)
    else:
        return url
def _proto_relative_url(self, url, scheme=None):
    if (url is None):
        return url
    if url.startswith('//'):
        if (scheme is None):
            scheme = self.http_scheme()
        return (scheme + url)
    else:
        return url