ImmutableMeta.py

class ImmutableMeta(ElementMeta):
    def __new__(cls, name, bases, namespace, **kwargs):
        def my_setattr(self, name, value):
            if hasattr(self, "_immutable") and self._immutable and not name.startswith("__"):
                raise AttributeError("this class was set immutable can not set %s, %s" % (name, self))
            return object.__setattr__(self, name, value)
        namespace["__setattr__"] = my_setattr

        def my_freeze(self):
            self._immutable = True
        namespace["freeze"] = my_freeze

        self = super().__new__(cls, name, bases, namespace)
        return self