simple binary tree implementation

simpletree

class Tree:
    def __init__(self):
        self.left = None
        self.right = None
        self.operator = None
    def to_array(self):
        new_array = []
        new_array.append(self.operator)
        for node in [self.left, self.right]:
            if isinstance(node, Tree):
                new_array.append(node.to_array())
            elif isinstance(node, list):
                new_array.append(node)
        return new_array
    def to_json(self):
        return json.dumps(self.to_array())