docs: def _check(self, terms):
          """Check terms do not contain unknown characters"""
          for t in terms:
              try:
                  _ = urllib.parse.quote(six.text_type(t).encode('utf8'))
              except:
                  self.logger.error('Unknown character in [{0}]!'.format(t))
                  self.logger.error('.... remove character and try again.')
                  raise EncodingError