'Get mapping between seat numbers and legislator identifiers.'

def _parse_seat_map(self):

    seat_map = {}
    page = self.lxmlize(self.lookup_url)
    options = page.xpath('//select[@id="member"]/option')
    for option in options:
        member_url = self.house_profile_url.format(option.attrib['value'])
        member_page = self.lxmlize(member_url)
        table = member_page.xpath('//table[@id="Table1"]')
        if table:
            res = re.search('seat    #:(\\d+)', table[0].text_content(), re.IGNORECASE)
            if res:
                seat_map[res.groups()[0]] = option.attrib['value']
    return seat_map
