code: def instances_set(self, root, reservation):
          
          instances = []
          for instance_data in root.find("instancesSet"):
              instances.append(self.instance(instance_data, reservation))
          return instances
docs: Parse instance data out of an XML payload.
  
          @param root: The root node of the XML payload.
          @param reservation: The L{Reservation} associated with the instances
              from the response.
          @return: A C{list} of L{Instance}s.