flattening a list with some elements being lists

[Gribouillis]

Using a generic function to dispatch according to the argument's type

>>> import functools
>>> @functools.singledispatch
... def flatten(x):
...     return [x]
... 
>>> @flatten.register(list)
... @flatten.register(tuple)
... def _(x):
...     return [z for y in x for z in flatten(y)]
... 
>>> a = [[1, 2, 3], [[4]], [5], [['spam','ham','bacon'] , [['foo','bar','baz']], ('x','y','z')], 6]
>>> flatten(a)
[1, 2, 3, 4, 5, 'spam', 'ham', 'bacon', 'foo', 'bar', 'baz', 'x', 'y', 'z', 6]