code: def get_standard(self):
          
          try:
              res = urlopen(PARSELY_PAGE_SCHEMA)
          except:
              return []
          text = res.read()
          if isinstance(text, bytes):
              text = text.decode('utf-8')
          tree = etree.parse(StringIO(text))
          stdref = tree.xpath("//div/@about")
          return [a.split(':')[1] for a in stdref]
docs: get list of allowed parameters