build_url.py

def url(self, url):
        """
        An internal method for build url
        """
        endpoint_url = provider['url'].replace('{format}', data_format)
        scheme, netloc, path, qs, fragment = urlsplit(endpoint_url)
        query_params = OrderedDict(parse_qsl(qs))
        query_params['url'] = url
        if self._params:
            query_params.update(self._params)
        query_params = urlencode(query_params, True)
        return urlunsplit((scheme, netloc, path, query_params, fragment))