Big problem plzz help..!!!

i can’t open my website.. after editing function.php file. this is the error msg

Fatal error: Cannot redeclare colormag_footer_copyright() (previously declared in /home/a8682390/public_html/wp-content/themes/colormag-child/functions.php:19) in /home/a8682390/public_html/wp-content/themes/colormag-child/functions.php on line 30