Warning : Undefined array key "width" in C:\xampp\htdocs\company\wp-content\themes\generatepress\inc\structure\header.php on line 127 and 128

I kept getting the error after using Generatepress theme in Wordpress for both width and height. Example as follows - Warning : Undefined array key "width" in C:\xampp\htdocs\company\wpcontent\themes\generatepress\inc\structure\header.php on line 127

    if ( '' !== $retina_logo_url ) {
        $attr['srcset'] = $logo_url . ' 1x, ' . $retina_logo_url . ' 2x';

        // Add dimensions to image if retina is set. This fixes a container width bug in Firefox.
        if ( function_exists( 'the_custom_logo' ) && get_theme_mod( 'custom_logo' ) ) {
            $data = wp_get_attachment_metadata( get_theme_mod( 'custom_logo' ) );

            if ( ! empty( $data ) ) {
                $attr['width'] = $data['width'];
                $attr['height'] = $data['height'];