Teaching this pattern without a clear warning should be considered harmful - using this pattern will lead to endless refactoring and makes your software untestable.
Please look up articles about dependency injection, and inversion of control, and learn that instead.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
The singleton pattern is an anti pattern - see the "Criticism" section in the Wikipedia article for a brief summary of all the reasons why:
en.wikipedia.org/wiki/Singleton_pa...
Teaching this pattern without a clear warning should be considered harmful - using this pattern will lead to endless refactoring and makes your software untestable.
Please look up articles about dependency injection, and inversion of control, and learn that instead.