Estimated time

20 minutes

Level of difficulty

Easy

Objectives

• improving the student's skills in operating with static and class methods

Scenario

• Create a class representing a luxury watch;
• The class should allow you to hold a number of watches created in the watches_created class variable. The number could be fetched using a class method named get_number_of_watches_created;
• the class may allow you to create a watch with a dedicated engraving (text). As this is an extra option, the watch with the engraving should be created using an alternative constructor (a class method), as a regular __init__ method should not allow ordering engravings;
• the regular __init__ method should only increase the value of the appropriate class variable;

The text intended to be engraved should follow some restrictions:

• it should not be longer than 40 characters;
• it should consist of alphanumerical characters, so no space characters are allowed;
• if the text does not comply with restrictions, an exception should be raised;

before engraving the desired text, the text should be validated against restrictions using a dedicated static method.

• Create a watch with no engraving
• Create a watch with correct text for engraving
• Try to create a watch with incorrect text, like 'foo@baz.com'. Handle the exception
• After each watch is created, call class method to see if the counter variable was increased