is_keras_tensor

`is_keras_tensor` is a function in Keras that checks whether an object is a Keras tensor or not. It returns `True` if the object is a Keras tensor, and `False` otherwise. Here's an example:

import tensorflow as tf
from tensorflow.keras.layers import Input, Dense

# create a Keras tensor
inputs = Input(shape=(10,))
hidden = Dense(32)(inputs)
outputs = Dense(1)(hidden)

# check if the tensor is a Keras tensor
print(tf.keras.backend.is_keras_tensor(inputs)) # True
print(tf.keras.backend.is_keras_tensor(hidden)) # True
print(tf.keras.backend.is_keras_tensor(outputs)) # True

In this example, `inputs`, `hidden`, and `outputs` are all Keras tensors, so `is_keras_tensor` returns `True` for all of them.