code: def get_ordered_children(self):
          
          ordered_keys = self.element.ordered_children if self.element.ordered_children is not None else []
          children = [self.indexes.get(k, None) for k in ordered_keys]
          return children
docs: Return the list of children ordered according to the element structure
  
          :return: a list of :class:`Element <hl7apy.core.Element>`