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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_weakref(func):
 """Get a weak reference to bound or unbound `func`. If `func` is unbound (i.e. has no __self__ attr) get a weakref.ref, otherwise get a wrapper that simulates weakref.ref. """

    if func is None:
        raise ValueError
    if not hasattr(func, '__self__'):
        return weakref.ref(func)
    return WeakMethod(func)