a question regarding conciseness

[Sean 'Shaleh' Perry]

> 
> for i in d.keys().sort():
>   do something
> 
> I get:
> 
> Traceback (innermost last):
>   File "<stdin>", line 1, in ?
> TypeError: loop over non-sequence
> 
> But I know that d.keys() returns a list to which the sort() function should 
> be applicable.

Yes keys() returns a sequence.  However sort() is a method of that sequence and
does not return anything.

mylist = alist.sort() # also an invalid statement

You could write a sort() function so that

for i in sort(d.keys()):
  do something

would work.