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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 disk_pick_polar(n=1, rng=None):
 """Return vectors uniformly picked on the unit disk. The unit disk is the space enclosed by the unit circle. Vectors are in a polar representation. Parameters n: integer Number of points to return. Returns ------- r: array, shape (n, 2) Sample vectors. """

    if rng is None:
        rng = np.random
    a = np.zeros([n, 2], dtype=np.float)
    a[:, 0] = np.sqrt(rng.uniform(size=n))
    a[:, 1] = rng.uniform(0.0, 2.0 * np.pi, size=n)
    return a