Python-сообщество

>>> a=[[(0,)], [(7,)],[(9,)]]
>>> print [i[0][0] for i in a]
[0, 7, 9]

def IterFlatten(iterable):
    if hasattr(iterable,"__iter__"):
        for seq in iterable:
            for e in IterFlatten(seq):
                yield e
    else:
        yield iterable

def Flatten(iterable,level=None):
    return list(IterFlatten(iterable))

print Flatten(a)