PHP error

<?php
class Dbh{

  private $servername;
  private $username;
  private $password;
  private $dbname;
  private $charset;

  protected function connect(){
    $this->servername = "localhost";
    $this->username = "root";
    $this->password = "";
    $this->dbname = "testdb";
    $this->charset = "utf8mb4";

    try{
      $dsn = "mysql:host=".$this->servename.";dbname=".$this->dbname.";charset=".$this->charset;
      $pdo = new PDO($dsn, $this->username, $this->password);
      $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
      return $pdo
    } catch (PDOException $e) {
      echo "connection failed: ".$e->getMessage();
    }

  }


}