What is the difference between tf.keras.applications.inception_v3 and tf.keras.applications.InceptionV3 ?

tf.keras.applications.inception_v3 is a model 

whereas tf.keras.applications.InceptionV3 is a function on that model.

tf.keras.applications.inception_v3 is the base model and tf.keras.applications.InceptionV3 is a function of it which instantiates the model. 

In fact, tf.keras.applications.InceptionV3() is an alias to tf.keras.applications.inception_v3.InceptionV3().