Parse a VocabularyKey from an Xml as per Healthvault
            schema.

            :param key_xml: lxml.etree.Element representing a single VocabularyKey

def parse_xml(self, key_xml):
        '''
            Parse a VocabularyKey from an Xml as per Healthvault
            schema.

            :param key_xml: lxml.etree.Element representing a single VocabularyKey
        '''
        xmlutils = XmlUtils(key_xml)
        self.name = xmlutils.get_string_by_xpath('name')
        self.family = xmlutils.get_string_by_xpath('family')
        self.version = xmlutils.get_string_by_xpath('version')
        self.description = xmlutils.get_string_by_xpath('description')

        self.language = xmlutils.get_lang()