docs: def validate_host_parameters(self, host_list, remote_user):
          '''
          Validate and set the host list and remote user parameters.
          '''
          if host_list is None:
              host_list = self.host_list
  
          if remote_user is None:
              remote_user = self.remote_user
  
          if host_list is None or remote_user is None:
              print "Host list [%s], remote user [%s] are required" % \
                    (host_list, remote_user)
              return (None, None)
  
          return (host_list, remote_user)