AttributeError: '……' object has no attribute '……'

代码
class TreeNode(object):
    def __int__(self, elem = None, _lichild = None, _rchild = None):
        self.elem = elem
        self.lchild = _lichild
        self.rchild = _rchild

class BTree(object):
    def __int__(self, _root = None):
        self.root = _root
        self.NodeQueue = []

    def add(self, elem):
        NodeQueue = []
        if self.root is None:
            self.root = TreeNode(elem)
        else:
            NodeQueue.append(self.root)
            while NodeQueue:
                temp = NodeQueue.pop(0)
                if temp.lchild == None:
                    temp.lchild = TreeNode(elem)
                    return
                elif temp.rchild == None:
                    NodeQueue.append(temp.lchild)
                    temp.rchild = TreeNode(elem)
                    return
                else:
                    NodeQueue.append(temp.lchild)
                    NodeQueue.append(temp.rchild)
                    return

if __name__ == "__main__":
    tree = BTree()
    tree.add(0)
运行结果及报错内容

Traceback (most recent call last):
File "xxx\BinaryTree\main.py", line 75, in
tree.add(0)
File "xxx\BinaryTree\main.py", line 19, in add
if self.root is None:
AttributeError: 'BTree' object has no attribute 'root'

求问应该如何解决

初始化函数少个 i
是 init，你写成了 int