safesort: safely sort heterogeneous collections on Python 2 and 3

safesort does what it says on the box: guarantees safe sorting of arbitrary heterogeneous lists across Python 2 and Python 3:

>>> list(sorted(["a", 1, None]))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: int() < str()
>>> list(safesort(["a", 1, None))
[None, 1, 'a']

Three ordering keys are attempted for each comparison:

1. Object: objA > objB
2. Type-and-object: (type(objA).__mro__, objA) > (type(objB).__mro__, objB)
3. Type-and-identity: (type(objA).__mro__, id(objA)) > (type(objB).__mro__, id(objB))

This guarantees a total ordering which is:

1. As consistent as possible
2. Broadly sensible: objects with similar types will be grouped together

For example:

>>> from safesort import safesort
>>> input = ['a', set([]), [], {}, 1, None]
>>> list(safesort(input))
[None, 1, {}, [], set([]), 'a']

Installation

safesort can be installed with Python 2 or Python 3 using pip or easy_install:

$ pip install safesort
- OR -
$ easy_install safesort