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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fetch_woeid(self, location):
 """Fetch a location's corresponding WOEID. Args: location: (string) a location (e.g. 23454 or Berlin, Germany). Returns: a string containing the location's corresponding WOEID or None if the WOEID could not be found. Raises: urllib.error.URLError: urllib.request could not open the URL (Python 3). urllib2.URLError: urllib2 could not open the URL (Python 2). xml.etree.ElementTree.ParseError: xml.etree.ElementTree failed to parse the XML document. """

        rss = self._fetch_xml(
            WOEID_LOOKUP_URL.format(quote(location)))
        try:
            woeid = rss.find("results/Result/woeid").text
        except AttributeError:
            return None
        return woeid