位置参数错误：如何解决此代码

Question

我试图拥有一个二分搜索树，并且该树包含包含人的节点，但是我得到了一个错误，即它没有采用位置参数。

class BST:
    def __init__(self):
        self.root = None

    def setRoot(self, ppl):
        self.root = Node(ppl)

    def insert(self, ppl):
        if (self.root is None):
            self.setRoot(ppl)       ##If there is no set root, it sets node as root
        else:
            self.insertNode(self.root, ppl)     ##if there is a root, it'll move onto insertNode

    def insertNode(self, currentNode, ppl):
        if (ppl <= currentNode.ppl):
            if (currentNode.leftChild):
                self.insertNode(currentNode.leftChild, ppl)
            else:
                currentNode.leftChild = Node(ppl)
        elif (ppl > currentNode.ppl):
            if (currentNode.rightChild):
                self.insertNode(currentNode.rightChild, ppl)
            else:
                currentNode.rightChild = Node(ppl)
Class Town:

    def add_citizen(self, ppl: Person):
        """Adds a person to the town."""
        self.q.inQ(ppl)
        Node(ppl)
        BST.insert(ppl)

我希望有一个二叉搜索树。

Error:File , line 141, in add_citizen
    BST.insert(ppl)
TypeError: insert() missing 1 required positional argument: 'ppl'