GP's point is that Python didn’t “pick” one but that it’s probably an accident of how the parser was implemented. It would see the `[]`, allocate a new object,

GP's point is that Python didn’t “pick” one but that it’s probably an accident of how the parser was implemented. It would see the `[]`, allocate a new object, then greedily assign it to the “variable”. The whole “tradeoff” argument doesn’t make sense when you consider that Python is the odd one out here with early binding. In fact, there’s been so many bugs with it that they had to invent a whole new syntax to fix it. When one says `intParam += 2`, why should they expect that to modify the default parameter? Yet when the default is a list, all of a sudden it’s fine. Python breaks the principle of least astonishment with default parameters, and it’s frustrating hearing people defend such a thing.