docs: def _create_dns_list(self, dns):
          """
          :param dns:
          :return:
          """
          if not dns:
              return None
  
          dns_list = []
  
          if isinstance(dns, six.string_types):
              if is_valid_ip(dns):
                  dns_list.append(dns)
              else:
                  raise ValueError("dns is required to be a valid ip adress. {0} was passed.".format(dns))
          elif isinstance(dns, list):
              for dns_entry in dns:
                  if is_valid_ip(dns_entry):
                      dns_list.append(dns_entry)
              else:
                  raise ValueError("dns is required to be a valid ip adress. {0} was passed.".format(dns))
  
          else:
              raise ValueError("dns and dns search must be a list or string. {0} was passed.".format(dns))
  
          return dns_list