class TreeNode():

    def __init__(self, key, value):
        self.childs = []
        self.key = key
        self.value = value

    def addChildNode(self, node):
        self.childs.append(node)

    def hasChilds(self):
        return (len(self.childs) > 0)

    def find(self, key):
        if key == self.key: return self
        for child in self.childs:
            r = child.find(key)
            if r != None: return r
        return None