index.php

<?php

interface 😺
{
    public function phpyh(string $x): iterable;
}

abstract class 😹 implements 😺
{
    abstract public function phpyh(int|string $x): array|\Generator;
}

interface  🐶
{
    public function phpyh(string $x, string $y): iterable;
}

final class 🐩 extends 😹 implements 😺, 🐶
{
    public function phpyh(int|string|float $x, string $y = 'C 8 марта!'): array
    {
        return [];
    }
}