An example of the transformation would help here

An example, that detects cycles in a graph, and doesn't do an update if the graph has cycles. class prevent_cycles(property): """ This uses nodes that point to only one other node: if there is a cycle in the current subgraph, it will detect that within O(n) """ def __init__(self, value): super().__init__() self._value = None self.__set__(value) def getter(self): return self._value def setter(self, value): if not turtle_and_hare(value): self._value = value else: raise Exception("cycle detected, shutting down") def deleter(self): del self._value def turtle_and_hare(self, other): """ Generic turtle and hare implementation. true if cycle, false if not. Returns True if cyclic from this point, false if it is not. """ turtle = other hare = other fieldname = self.__name__ # this assuming that properties have access to their name, but that # would also be the same as a function. while True: if hare is None: return False hare = getattr(hare, fieldname) if hare is None: return False if hare is turtle: return True hare = getattr(hare, fieldname) turtle = getattr(turtle, fieldname) if hare is turtle: return True class A(object): def __init__(self, parent): @prevent_cycles self.parent = parent This would prevent cycles from being created in this object A, and would make some highly reusable code. The same can be done for @not_none, etc, to prevent some states which may be unwanted.