[joshuamorton]

A good answer is because you don't necessarily know if the thing you're getting is a list, a tuple, or a RepeatedCompositeFieldContainer (a protobuf list), or some other type that meets the Sequence/MutableSequence abstract base class contract. `if not foo` will check that they're all empty, while `if foo == []` will have unexpected behavior if foo starts returning a set tomorrow.

The generalization of this is to code against as generic an api as possible, you wouldn't do `list.__eq___(x, y)` in your code, but you're suggesting almost exactly that.

(granted you can still run into this kind of issue if foo is a generator, but that's a less common way to explode).

The style guide does tell you to use explicit `x is None`, instead of implicit bool when checking noneness, specifically to disambiguate between binary and ternary values, but usually that's not what you want.