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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 scale_sfs(s):
 """Scale a site frequency spectrum. Parameters s : array_like, int, shape (n_chromosomes,) Site frequency spectrum. Returns ------- sfs_scaled : ndarray, int, shape (n_chromosomes,) Scaled site frequency spectrum. """

    k = np.arange(s.size)
    out = s * k
    return out