Frustration with iteritems not existing for list type

def flatten(obj):
    """ flattens a nested data structure into a list of (value, path) tuples """
    vals = []
    def rec(obj, path):
        def append(k, v):
            new_path = path + (k,)
            if hasattr(v, '__iter__'): rec(v, new_path)
            else: vals.append((v, new_path))
        try:
            if hasattr(obj, 'iteritems'):
                for k,v in obj.iteritems(): append(k,v)
            else:
                for k,v in enumerate(obj): append(k,v)
        except:
            vals.append((obj, path))
    rec(obj, ())
    return vals