Github.php on line 222 = Fatal error

Please help.

Updated Wordpress and all plugins today. No I can not access the frontend website NOR the backend admin. I receive:

Fatal error: Call to undefined function get_plugins() in /home4/gregorio/public_html/family/wp-content/themes/valenti/library/extensions/github.php on line 222

Desperately need "easy to understand" instructions for fixing http://ift.tt/1RV5Eer

Many thanks,

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