classes/Connection.php
public function pdo(PDO $pdo = null)
    {
        if ($pdo) {
            $this->pdo = $pdo;
        }

        return $this->pdo;
    }
public function pdo(PDO $pdo = null)
    {
        if ($pdo) {
            $this->pdo = $pdo;
        }

        return $this->pdo;
    }
public function pdo ( PDO $ pdo = null ) { if ( $ pdo ) { $ this -> pdo = $ pdo ; } return $ this -> pdo ; }
Get or set PDO instance

@param PDO $pdo (optional)
@return PDO
Get or set PDO instance