https://refactoring.guru/design-patterns/singleton

1. Singleton is a creational design pattern that lets you ensure that a class has only one instance, while providing a global access point to this instance..
2. A class of which only a single instance can exist

1. Use the Singleton pattern when a class in your program should have just a single instance available to all clients; for example, a single database object shared by different parts of the program.
2. Use the Singleton pattern when you need stricter control over global variables.

https://refactoring.guru/design-patterns/singleton#checklist

python main.py
python example.py