如何检查tensorarray中的索引是否已初始化？

import tensorflow as tf

# 创建一个TensorArray对象
tensor_array = tf.TensorArray(dtype=tf.float32, size=5, dynamic_size=True)

# 初始化索引为2的元素
tensor_array = tensor_array.write(2, tf.constant(3.14))

# 检查索引为2的元素是否已初始化
is_initialized = tf.not_equal(tensor_array.read(2), None)

with tf.Session() as sess:
    sess.run(tf.global_variables_initializer())
    result = sess.run(is_initialized)
    print(result)

True