sim3x

outf = codecs.getwriter('utf-8')(sys.stdout, errors='replace')

>>> import json
>>> print(json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4))
{
    "4": 5,
    "6": 7
}

In [1]: l = ['Mary', 'had', 'a', 'little', 'lamb']
In [2]: l.sort(key = lambda s: len(s))
In [3]: l
Out[3]: ['a', 'had', 'Mary', 'lamb', 'little']ґ