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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 joint_sfs_scaled(dac1, dac2, n1=None, n2=None):
 """Compute the joint site frequency spectrum between two populations, scaled such that a constant value is expected across the spectrum for neutral variation, constant population size and unrelated populations. Parameters dac1 : array_like, int, shape (n_variants,) Derived allele counts for the first population. dac2 : array_like, int, shape (n_variants,) Derived allele counts for the second population. n1, n2 : int, optional The total number of chromosomes called in each population. Returns ------- joint_sfs_scaled : ndarray, int, shape (n1 + 1, n2 + 1) Array where the (i, j)th element is the scaled frequency of variant sites with i derived alleles in the first population and j derived alleles in the second population. """


    # compute site frequency spectrum
    s = joint_sfs(dac1, dac2, n1=n1, n2=n2)

    # apply scaling
    s = scale_joint_sfs(s)

    return s