[python] In Python, how do I determine if an object is iterable?

I often find convenient, inside my scripts, to define an iterable function. (Now incorporates Alfe's suggested simplification):

import collections

def iterable(obj):
    return isinstance(obj, collections.Iterable):

so you can test if any object is iterable in the very readable form

if iterable(obj):
    # act on iterable
else:
    # not iterable

as you would do with thecallable function

EDIT: if you have numpy installed, you can simply do: from numpy import iterable, which is simply something like

def iterable(obj):
    try: iter(obj)
    except: return False
    return True

If you do not have numpy, you can simply implement this code, or the one above.