以下Python代码中，符合二叉树节点类构造规范的是？

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

class TreeNode:
    def init(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

class TreeNode:
    val = 0
    left = None
    right = None
    def __init__(self, val, left, right):
        val = val
        left = left
        right = right

class TreeNode:
    def __init__(val=0, left=None, right=None):
        val = val
        left = left
        right = right