Run code TF-GPU erroring

[Eslam2011]

I run python code using TF-GPU on this image tensorflow/tensorflow:latest-gpu, and they alot of errors in code such as:

x_idxs = tf.placeholder(tf.int64, shape=[None,2])
AttributeError: module 'tensorflow' has no attribute 'placeholder'

I solved it by using
import tensorflow.compat.v1 as tf
tf.disable_v2_behavior()

### But why this error, I think the code must run without any error?