How to flatten a hetrogenous list of list into a single list in python? [duplicate]

Here is a relatively simple recursive version which will flatten any depth of list

l = [35,53,[525,6743],64,63,[743,754,757]]

def flatten(xs):
    result = []
    if isinstance(xs, (list, tuple)):
        for x in xs:
            result.extend(flatten(x))
    else:
        result.append(xs)
    return result

print flatten(l)