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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 ensure_rng(random_state=None):
 """ Creates a random number generator based on an optional seed. This can be an integer or another random state for a seeded rng, or None for an unseeded rng. """

    if random_state is None:
        random_state = np.random.RandomState()
    elif isinstance(random_state, int):
        random_state = np.random.RandomState(random_state)
    else:
        assert isinstance(random_state, np.random.RandomState)
    return random_state