[masklinn]

> For example "a" + 1 is an error, why is u"a" + "s" not an error?

"a" + b"s" is an error in Python 3.

[gardentheory]

Sorry, that was my point. Strengthening the types in python3 solves the problem without static typing being needed at all.

[masklinn]

ok.

Static types solve it earlier though, especially for little-exercised code paths which could be forgotten or missed in testing.