Python enum prevent invalid attribute assignment

When I use the Functional API to create an enum, I get back an enum object that allows arbitrary assignment (i.e. it has a __dict__):

e = enum.Enum('Things',[('foo',1),('bar',2)])
e.baz = 3

The item does not appear in the list:

list(e)
[<foo.foo: 1>, <foo.bar: 2>]

But it can still be referenced:

if thing == e.baz: ...

Now while it seems unlikely to ever occur, one of the reasons I want to use an enum is to prevent spelling mistakes and string literals, and for those things to be caught when a module is imported or as early as possible.

Is there a way to dynamically build an enum that behaves more like a __slots__ object that does not allow arbitrary attributes to be assigned?

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