Conexao PDO

<?php

class Conn {

    private static $Connect = null;
    private static $host = 'localhost';
    private static $user = 'root';
    private static $pass = '';
    private static $dbname = 'grupo++';

    private static function Connection() {

        try {

            if (self::$Connect == null) {

                $options = [
                    PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES UTF8"
                ];
                self::$Connect = new PDO("mysql:dbname=" . self::$dbname . ";host=" . self::$host, self::$user, self::$pass, $options);

                self::$Connect->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            }
        } catch (PDOException $e) {
            die($e->getMessage());
        }

        return self::$Connect;
    }

    public static function getConn() {
        return self::Connection();
    }

    public static function getQuery($sql) {
        $stmt = self::getConn()->query($sql);
        return $stmt->fetchAll();
    }

}

var_dump(Conn::getQuery('SELECT * FROM usuarios'));