code: def sfs_scaled(dac, n=None):
      
  
      # compute site frequency spectrum
      s = sfs(dac, n=n)
  
      # apply scaling
      s = scale_sfs(s)
  
      return s
docs: Compute the site frequency spectrum scaled such that a constant value is
      expected across the spectrum for neutral variation and constant
      population size.
  
      Parameters
      ----------
      dac : array_like, int, shape (n_variants,)
          Array of derived allele counts.
      n : int, optional
          The total number of chromosomes called.
  
      Returns
      -------
      sfs_scaled : ndarray, int, shape (n_chromosomes,)
          An array where the value of the kth element is the number of variants
          with k derived alleles, multiplied by k.