public function __construct( $opt = '' ) {
    $this->method = 'ftpsockets';
    $this->errors = new WP_Error();

    // Check if possible to use ftp functions.
    if ( ! include_once ABSPATH . 'wp-admin/includes/class-ftp.php' ) {
      return;
    }
    $this->ftp = new ftp();

    if ( empty( $opt['port'] ) ) {
      $this->options['port'] = 21;
    } else {
      $this->options['port'] = (int) $opt['port'];
    }

    if ( empty( $opt['hostname'] ) ) {
      $this->errors->add( 'empty_hostname', __( 'FTP hostname is required' ) );
    } else {
      $this->options['hostname'] = $opt['hostname'];
    }

    // Check if the options provided are OK.
    if ( empty( $opt['username'] ) ) {
      $this->errors->add( 'empty_username', __( 'FTP username is required' ) );
    } else {
      $this->options['username'] = $opt['username'];
    }

    if ( empty( $opt['password'] ) ) {
      $this->errors->add( 'empty_password', __( 'FTP password is required' ) );
    } else {
      $this->options['password'] = $opt['password'];
    }
  }