Grab the column definition of a table from the EPA using a combination
        of regular expressions and lxml.

def grab_definition(self, url):
        """
        Grab the column definition of a table from the EPA using a combination
        of regular expressions and lxml.
        """
        re_description = re.compile('Description:(.+?\\n)')
        re_table_name = re.compile("(\w+ Table.+)")
        if url.startswith('//'):
            url = 'http:' + url
        elif url.startswith('/'):
            url = 'http://www.epa.gov' + url
        try:
            html = urlopen(url).read()
            doc = lh.fromstring(html)
            main = doc.cssselect('#main')[0]
            text = main.text_content()
            definition = re_description.search(text).group(1).strip()
        except (AttributeError, IndexError, TypeError, HTTPError):
            print url
        else:
            value = re_table_name.sub('', definition)
            return value
        return url