code: def moving_delta_tajima_d(ac1, ac2, size, start=0, stop=None, step=None):
      
  
      d1 = moving_tajima_d(ac1, size=size, start=start, stop=stop, step=step)
      d2 = moving_tajima_d(ac2, size=size, start=start, stop=stop, step=step)
      delta = d1 - d2
      delta_z = (delta - np.mean(delta)) / np.std(delta)
      return delta_z
docs: Compute the difference in Tajima's D between two populations in
      moving windows.
  
      Parameters
      ----------
      ac1 : array_like, int, shape (n_variants, n_alleles)
          Allele counts array for the first population.
      ac2 : array_like, int, shape (n_variants, n_alleles)
          Allele counts array for the second population.
      size : int
          The window size (number of variants).
      start : int, optional
          The index at which to start.
      stop : int, optional
          The index at which to stop.
      step : int, optional
          The number of variants between start positions of windows. If not
          given, defaults to the window size, i.e., non-overlapping windows.
  
      Returns
      -------
      delta_d : ndarray, float, shape (n_windows,)
          Standardized delta Tajima's D.
  
      See Also
      --------
      allel.stats.diversity.moving_tajima_d