>>> dct = {
...     "1": "a", 
...     "3": "b", 
...     "8": {
...         "12": "c", 
...         "25": "d"
...     }
... }
>>> 
>>> dct.keys()
['1', '8', '3']
>>> for key in dct.keys(): print key
...
1
8
3
>>>