### Z8SLacSv.py
<function Tree.__len__.<locals>.<lambda> at 0x7fe558fca598>
<__main__.Tree object at 0x7fe558fcfb70> <__main__.Tree object at 0x7fe558fcfc18> 3
1
<__main__.Tree object at 0x7fe5598725f8> <__main__.Tree object at 0x7fe558fbec88> 2
1
None None 1
1
None None 1
Traceback (most recent call last):
  File "../decompiler.py", line 219, in <module>
    tree()
  File "../decompiler.py", line 61, in tree
    print(len(t))
  File "../decompiler.py", line 56, in __len__
    return self.preorder(function=lambda data, d : 1, join=lambda l,r,c : ((0 if l is None else l) + (0 if r is None else r) + c))
  File "../decompiler.py", line 20, in preorder
    l = self.left.preorder(function, depth+1)
  File "../decompiler.py", line 20, in preorder
    l = self.left.preorder(function, depth+1)
  File "../decompiler.py", line 26, in preorder
    return join(l,r,c)
TypeError: 'int' object is not callable
### 7YtNyaTx.py
class Tree:
    def __init__(self, data=None, left=None, right=None):
        self.left = left
        self.right = right
        self.data = data
    
    def preorder(self, function=lambda data, d : None, join=lambda l,r,c : None, depth=0):
        print(join)
        l = None
        r = None
        print(self.left, self.right, self.data)
        if self.left is not None:
            l = self.left.preorder(function, depth+1)
        if self.right is not None:
            r = self.left.preorder(function, depth+1)
        c = function(self.data, depth)
        print(join)
        print(l,r,c)
        return join(l,r,c)
        
    def inorder(self, function=lambda data, d : None, join=lambda l,r,c : None, depth=0):
        l = None
        r = None
        if self.left is not None:
            l = self.left.preorder(function, depth+1)
        c = function(self.data, depth)
        if self.right is not None:
            r = self.left.preorder(function, depth+1)
        return join(l,r,c)
        
    def postorder(self, function=lambda data, d : None, join=lambda l,r,c : None, depth=0):
        l = None
        r = None
        c = function(self.data, depth)
        if self.left:
            l = self.left.preorder(function, depth+1)
        if self.right:
            r = self.left.preorder(function, depth+1)
        return join(l,r,c)
        
    def __len__(self):
  #      def join(left, right, curr):
  #          sum = curr
  #          if left is not None:
  #              sum += left
  #          if right is not None:
  #              sum += right
  #          return sum
        return self.preorder(function=lambda data, d : 1, join=lambda l,r,c : ((0 if l is None else l) + (0 if r is None else r) + c))
        

def tree():
    t = Tree(3, Tree(2, Tree(1), Tree(4)), Tree(5, Tree(6), Tree(7)))
    print(len(t))