Fatal error: Uncaught Error: Call to undefined function Av_Responsive_Images() i

I upgraded my site to the last time, but I am having this problem

Fatal error: Uncaught Error: Call to undefined function Av_Responsive_Images() in /home/******/tolgahanturk.com/wp-content/themes/icmimarlik/functions.php:168 Stack trace: #0 /home/*****/tolgahanturk.com/wp-settings.php(508): include() #1 /home/****/tolgahanturk.com/wp-config.php(161): require_once(‘/home/****/…’) #2 /home/u8753672/tolgahanturk.com/wp-load.php(37): require_once(‘/home/*****/…’) #3 /home/*****/tolgahanturk.com/wp-blog-header.php(13): require_once(‘/home/****/…’) #4 /home/*****/tolgahanturk.com/index.php(17): require(‘/home/*****/…’) #5 {main} thrown in /home/*****/tolgahanturk.com/wp-content/themes/icmimarlik/functions.php on line 168

MY SITE IS NOT WORKING.