code: def joint_sfs_scaled(dac1, dac2, n1=None, n2=None):
      
  
      # compute site frequency spectrum
      s = joint_sfs(dac1, dac2, n1=n1, n2=n2)
  
      # apply scaling
      s = scale_joint_sfs(s)
  
      return s
docs: 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.