no more comparisons

[Terry Reedy]

| > Hmm, wasn't aware they were taking it that far.  You should almost
| > always avoid using the cmp parameter because it's very inefficient;
|
| I don't see what's so inefficient about it necessarily.

The key function is called once per list item, for n calls total.  The 
comparision function is called once per comparision.  There are at least 
n-1 such calls and typically something on the order of n * lg2(n) calls.