gistfile1.py

class PickleProperty(db.TextProperty):

    def get_value_for_datastore(self, model_instance):
        value = self.__get__(model_instance, model_instance.__class__)
        return db.Text(self._deflate(value))

    def validate(self, value):
        return value

    def make_value_from_datastore(self, value):
        return self._inflate(value)

    def _inflate(self, value):
        try:
            val = pickle.loads(base64.decodestring(unicode(value)))
        except:
            val = ""
        return val

    def _deflate(self, value):
        val = pickle.dumps(value)
        return base64.encodestring(val)