https://stackoverflow.com/questions/59729820/are-functions-defined-in-a-class-are-by-default-static-if-yes-then-why#59729820
How to permanently typecast class properties in PHP?
https://stackoverflow.com/questions/59804066/what-are-the-limitations-of-inheriting-from-abstract-class-that-are-remedied-by
https://stackoverflow.com/questions/59954412/in-javascript-can-we-return-non-objects-by-reference
https://stackoverflow.com/questions/59668056/what-are-parent-and-child-methods-in-php-and-how-can-we-override-that-parent-met
https://stackoverflow.com/questions/59804066/what-are-the-particular-features-of-inheriting-from-abstract-class-that-are-not
https://stackoverflow.com/questions/59729820/why-are-non-static-functions-assessible-without-object-initialization-in-php7
