docs: def _get_hosts_from_names(self, names):
          """ validate hostnames from a list of names
          """
          result = set()
          hosts = map(lambda x: x.strip(), names.split(','))
          for h in hosts:
              if valid_hostname(h.split(':')[0]):
                  result.add(h if ':' in h else '%s:%d' % (h, self.PORT))
              else:
                  raise conferr('Invalid hostname: %s' % h.split(':')[0])
          return list(result)