Notice: Undefined index: use_custom_image

I’m having a problem in my website, when my author box appears. This notice appears:

Notice: Undefined index: use_custom_image in /hermes/bosnaweb10a/b2701/ipg.economizareinvestirc/wp-content/plugins/custom-about-author/display-about-author-block.php on line 134

And the line 134 is:
if($author[CAA_Profile_DB::use_custom_image]){

after this, is:
if($author[CAA_Profile_DB::use_custom_image]){
//use custom author image url
$author_image_url = caa_html_entity_decode( $author[CAA_Profile_DB::custom_image_url]);
$author_image = ‘<img src=”‘.$author_image_url.'” width=”‘.$image_size.'” height=”‘.$image_size.'” />’;
}

https://www.ads-software.com/plugins/custom-about-author/