не может видеть ошибки синтаксиса

Question

Я пытаюсь построить двойную библиотеку дерева поиска, и я получаю ошибку синтаксиса на мой кусок кода:

class Node: 
    """ 
    Tree node: Left and Right child + data which can be any object 
    """ 
    def __init__(self,data): 
     """ 
     Node constructor 
     """ 
     self.left = None 
     self.right = None 
     self.data = data 

def insert(self,data):      # self --> object self.data 
    """ 
    Insert new node with data 
    """ 
    if data < self.data:     # insert data less than current root 
     if self.left is None:    # if left node is empty, 
      self.left = Node(data)   # object left --> Node with new data 
     else: 
      self.left.insert(data)   # if left node is not empty, go insert again 
    else: 
     if self.right is None:    # insert data greater than current node 
      self.right = Node(data)  # object right --> Node with new data 
     else: 
      self.right.insert(data)  # if not empty, run insert again 


def lookup(self, data, parent = None): 
    """ 
    Lookup node containing data 
    """ 
    if data < self.data: 
     if self.left is None: 
      return None, None 
     return self.left.lookup(data,self) 
    elif data > self.data: 
     if self.right is None: 
      return None, None 
     return self.right.lookup(data,self) 
    else: 
     return self, parent 

def delete(self, data): 
    """ 
    delete node containing data 
    """ 

    """ no child """ 
    if children_count == 0: 
     # if node has no children, remove it 
     if parent.left is node:  # if parent is pointing to current node 
      parent.left = None   # set parent pointing left to None 
     else: 
      parent.right = None  # else set parent pointing right to None 
     del node      # del node 

    """ 1 child """  
    elif children_count == 1: 
     # if node has 1 child 
     # replace node by it's child 
     if node.left: 
      n = node.left 
     else: 
      n = node.right 
     if parent: 
      if parent.left is node: 
       parent.left = n 
      else: 
       parent.right = n 
     del node 

    """ 2 children """ 
    else: 
     # if node has 2 children 
     # find its successor 
     parent = node          # parent is equal to current node target of deletion 
     successor = node.right        # successor is right of the node 
     while successor.left:         
      parent = successor        
      successor = successor.left 
     # replace node data by its successor data 
     node.data = successor.data 
     #fix successor's parent's child 
     if parent.left == successor: 
      parent.left = successor.right 
     else: 
      parent.right = successor.right 


def children_count(self): 
    """ Return the number of children """ 
    if node is None: 
     return None 
    cnt = 0 
    if self.left: 
     cnt += 1 
    if self.right: 
     cnt += 1 
    return cnt 


# method to print tree in order. Use recursion inside print_tree() to walk the tree breath-first 

def print_tree(self): 
    if self.left: 
     self.left.print_tree() 
    print self.data, 
    if self.right: 
     self.right.print_tree() 

ошибка:

Traceback (most recent call last): 
    File "<pyshell#10>", line 1, in <module> 
    import BSTlib 
    File "BSTlib.py", line 78 
    elif children_count == 1: 
    ^

Кажется, я не вижу, что не так. [Может кто-нибудь помочь мне указать на это? Спасибо!

Answer 1

Это ошибка с docstring и пробелами. Запустить этот код:

if False: 
    print 'hi' 

"""1 child""" 
elif True: 
    print 'sdf' 

И вы получите аналогичный синтаксический эффект.

Удалите строку документации (или просто переместить его) и удалить лишние пробелы:

if False: 
    print 'hi' 
elif True: 
    print 'sdf' 

---

Если вам нужно комментировать, а затем просто использовать хэш #:

if False: 
    print 'hi' 
# 1 child 
elif True: 
    print 'sdf'