code: def scale_joint_sfs_folded(s, n1, n2):
        # noqa
      out = np.empty_like(s)
      for i in range(s.shape[0]):
          for j in range(s.shape[1]):
              out[i, j] = s[i, j] * i * j * (n1 - i) * (n2 - j)
      return out
docs: Scale a folded joint site frequency spectrum.
  
      Parameters
      ----------
      s : array_like, int, shape (m_chromosomes//2, n_chromosomes//2)
          Folded joint site frequency spectrum.
      n1, n2 : int, optional
          The total number of chromosomes called in each population.
  
      Returns
      -------
      joint_sfs_folded_scaled : ndarray, int, shape (m_chromosomes//2, n_chromosomes//2)
          Scaled folded joint site frequency spectrum.