Call to undefined function get_plugins()

Hello, I am using the last version of your plugin (2.2.9) but I just noticed it is fullfilling my error_log with something related to get_plugins() function.
The error log is the following:

PHP Fatal error:  Uncaught Error: Call to undefined function get_plugins() in /home/public_html/wp-content/plugins/wp-optimize/includes/wp-optimize-database-information.php:497
Stack trace:
#0 /home/public_html/wp-content/plugins/wp-optimize/includes/wp-optimize-database-information.php(411): WP_Optimize_Database_Information->get_all_installed_plugins()
#1 /home/public_html/wp-content/plugins/wp-optimize/includes/class-wp-optimizer.php(297): WP_Optimize_Database_Information->is_table_using_by_plugin('wp_blc_fi...')
#2 /home/public_html/wp-content/plugins/wp-optimize/wp-optimize.php(1288): WP_Optimizer->get_tables()
#3 /home/public_html/wp-content/plugins/wp-optimize/wp-optimize.php(1279): WP_Optimize->update_corrupted_tables_count()
#4 /home/public_html/wp-includes/class-wp-hook.php(286): WP_Optimize->do_plugin_cron_tasks()
#5 /home/public_html/wp-content/plugins/wp-optimize/includes/class-wp-optimizer.php(2)in /home/public_html/wp-content/plugins/wp-optimize/includes/wp-optimize-database-information.php on line 497

Do you think I can do something to solve the issue?
Thanks,
Emanuele