What's the proper way to subclass `object.__getitem__()` but fall back on the default behavior? I want to make this look like a dict that behaves dynamically (but consistently) for any possible key.

```
class MyObj(object):
    """MyObj()[k] returns 1 for any key k that ends in '_q',
       default item lookup behavior otherwise"""
    mypattern = re.compile(r'_q$')
    def __getitem__(self, k):
        if self.mypattern.match(k):
            return 1
        else:
            ???

```

I tried calling `return super(TFConverter, self).__getitem__(k)` and it tells me `AttributeError: 'super' object has no attribute '__getitem__'`