在python中打印类实例的元素列表

Question

鉴于下面的代码，我只有一个问题。我试图打印“Noeud”类实例的元素列表（list\ fils），但它给出了以下结果（节点0的示例）：

Children of Node  0  are:  [<__main__.Noeud object at 0x7f7d1a5009b0>, <__main__.Noeud object at 0x7f7d1a500b38>]

如何打印列表中的元素？以下是我的程序：

class Noeud:
    def __init__(self,val):
        self.val=val
        self.list_fils=[] #list containing children of the instance


 # K is number of levels of our binary tree
 #if we have k=2 levels, we need to iterate until Node with index (2^0)-1=0
 #if we have k=3 levels, we need to iterate until Node with index (2^0 + 2^1)-1 = 2
 #if we have k=4 levels, we need to iterate until Node with index (2^0 + 2^1 + 2^2)-1=6
 #if we have k levels, we need to iterate until Node with index (2^0+ 2^1 +.....+2^(k-2))
 def stop_index_for_level(K):
      Sum=0
      for x in range(K-1):
          Sum+=2**x
      return Sum-1

  #for each node(i) in l we add children of this node(i) to the list_fils attribute
  def Exo3(K,l):
      Debut=1
      for i in range(stop_index_for_level(K)+1):
          Fin=Debut+2
          l[i].list_fils.extend(l[Debut:Fin])
          Debut=Fin

  #our binary tree example (Note: each level must be completed)
                #0
              #/  \
             #1   2
            #/\  /\
           #3 4 5 6
  List_Nodes=[Noeud(i) for i in range(7)] #[0,1,2,3,4,5,6]
  Exo3(3,List_Nodes)

  for x in range(len(List_Nodes)):
      print("Children of Node ",List_Nodes[x].val," are: ",List_Nodes[x].list_fils)