>>> import operator

>>> values = dict(one=1, two=2, three=3)
>>> sorted(values.items())
[('one', 1), ('three', 3), ('two', 2)]
>>> sorted(values.items(), key=lambda item: item[1])
[('one', 1), ('two', 2), ('three', 3)]

>>> get_value = operator.itemgetter(1)
>>> sorted(values.items(), key=get_value)
[('one', 1), ('two', 2), ('three', 3)]

------------------------------------------------------------------------------

>>> key = lambda item: item[1]

>>> def key(item):
...     return item[1]

------------------------------------------------------------------------------

>>> def key(spam): return spam.value

>>> key = lambda spam: spam.value