Bug: PHP Error on Code generation

Error on Code generation.

In file “wp-content/plugins/wp-download-codes/includes/helpers/db.php” line 302 I get PHP errors because variable $code_db response NULL instead 0.

Fix for this, change line 302

from

$code_unique = ( sizeof( $code_db ) == 0);

to

$code_unique = ( @sizeof( $code_db ) === 0 || $code_db === NULL);