Singleton Creational Design Pattern in PHP

BEGIN TESTING SINGLETON PATTERN

BookBorrower1 asked to borrow the book
BookBorrower1 Author and Title:
Design Patterns by Gamma, Helm, Johnson, and Vlissides

BookBorrower2 asked to borrow the book
BookBorrower2 Author and Title:
I don't have the book

BookBorrower1 returned the book

BookBorrower2 Author and Title:
Design Patterns by Gamma, Helm, Johnson, and Vlissides

END TESTING SINGLETON PATTERN