docs: def draw_slices(hist, func=np.sum, **kwargs):
      """ Draw horizontal and vertical slices through histogram """
      from mpl_toolkits.axes_grid1 import make_axes_locatable
      kwargs.setdefault('ls','-')
      ax = plt.gca()
  
      data = hist
  
      # Slices
      vslice = func(data,axis=0)
      hslice = func(data,axis=1)
  
      npix = np.array(data.shape)
      #xlim,ylim = plt.array(zip([0,0],npix-1))
      xlim = ax.get_xlim()
      ylim = ax.get_ylim()
      #extent = ax.get_extent()
      #xlim =extent[:2]
      #ylim = extent[2:]
  
      # Bin centers
      xbin = np.linspace(xlim[0],xlim[1],len(vslice))#+0.5 
      ybin = np.linspace(ylim[0],ylim[1],len(hslice))#+0.5
      divider = make_axes_locatable(ax)
      
      #gh2 = pywcsgrid2.GridHelperSimple(wcs=self.header, axis_nums=[2, 1])
      hax = divider.append_axes("right", size=1.2, pad=0.05,sharey=ax,
                                axes_class=axes_divider.LocatableAxes)
      hax.axis["left"].toggle(label=False, ticklabels=False)
      #hax.plot(hslice, plt.arange(*ylim)+0.5,'-') # Bin center
      hax.plot(hslice, ybin, **kwargs) # Bin center
      hax.xaxis.set_major_locator(MaxNLocator(4,prune='both'))
      hax.set_ylim(*ylim)
  
      #gh1 = pywcsgrid2.GridHelperSimple(wcs=self.header, axis_nums=[0, 2])
      vax = divider.append_axes("top", size=1.2, pad=0.05, sharex=ax,
                                axes_class=axes_divider.LocatableAxes)
      vax.axis["bottom"].toggle(label=False, ticklabels=False)
      vax.plot(xbin, vslice, **kwargs) 
      vax.yaxis.set_major_locator(MaxNLocator(4,prune='lower'))
      vax.set_xlim(*xlim)
  
      return vax,hax