code: def get_total(tots, node):
      
      if (node.is_leaf() or node.is_root()):
          return 0
      else:
          ## Get counts on down edges. 
          ## How to treat polytomies here?
          if len(node.children) > 2:
              down_r = node.children[0]
              down_l = node.children[1]
              for child in node.children[2:]:
                  down_l += child
          else:
              down_r, down_l = node.children
          lendr = sum(1 for i in down_r.iter_leaves())
          lendl = sum(1 for i in down_l.iter_leaves())
  
          ## get count on up edge sister
          up_r = node.get_sisters()[0]
          lenur = sum(1 for i in up_r.iter_leaves())
  
          ## everyone else
          lenul = tots - (lendr + lendl + lenur)
  
          ## return product
          return lendr * lendl * lenur * lenul
docs: get total number of quartets possible for a split