In a conversation with Ethan Furman (the author of the enum module) I've been informed that Enum automatically checks whether the _missing_ method has returned an instance of the correct class, and raises a TypeError if not. (Link: https://stackoverflow.com/a/52064774/1222951)

However, this simply does not happen.

```
import enum

class MyEnum(enum.Enum):
    FOO = "foo"

    @classmethod
    def _missing_(cls, value):
        return 5

print(MyEnum('bar'))  # output: 5
```