Implement a Product class with the following attributes (price, product_name, brand). Create a custom string representation for your product class by using the dunder methods __str__ and __repr__. Keep the goals for these methods in mind __str__ is targeted at end users and is about readability while the focus of __repr__ is to provide an unambiguous representation that can be used for debugging and development. Both methods should show the value of all attributes of the instance. Write test code for both methods.