<?php

class Service
{
    public function __construct($msg)
    {
    }

    public function getSnake($sentence): string|array|null
    {
        return preg_replace_callback('/([A-Z])/', [__CLASS__, 'convertToSnakeCase'], $sentence);
    }

    private function convertToSnakeCase($c) {
        return "_" . strtolower($c[1]);
    }
}