repeat steps and but type hello instead of python displays about the same error message as before python doesn' differentiate between types of wrong input it only knows that the input type is incorrect and therefore unusable figure - the applica tion verifies the value is in the right range and outputs message figure - typing the wrong type of informa tion results in an error message the best applications use various kinds of range checking to ensure that the application behaves in predictable manner the more predictable an application becomesthe less the user thinks about the application and the more time the user spends on performing useful work productive users tend to be lot happier than those who constantly fight with their applications