1.  To switch tf.keras to use Keras 2 (tf-keras), set the environment
        variable TF_USE_LEGACY_KERAS=1 directly or in your python program by
        import os;os.environ["TF_USE_LEGACY_KERAS"]=1. Please note that this
        will set it for all packages in your Python runtime program

*   1.  Change import of keras from tensorflow as follows
*   import tensorflow.keras as keras and import keras to import tf_keras as
    keras