python - Call of sort method returns unexpected result -

i have dictionary:

{'three': 3, 'two': 2, 'one': 1}

and need make operations tuple of keys dictionary, i'm trying use code:

list(d.keys()) # need sort list(d.keys()).sort() # why such construction returns none? (use print() track it)

i'm using vs 2013 , intellisense prompts me sort method when print list(d.keys()). i'm missing?

p.s such construction works well:

l = list(d.keys()) l.sort()

thank you!

the .sort() method modifies list in place , returns none. use on list returned method need save list in variable.

l = list(d.keys()) l.sort() print l

if want eliminate temporary variable, use sorted:

print sorted(d.keys())

Deter