Unable to create directory

I am getting this error when I try Define (‘WP_Debug’, True);

Warning: mysqli_escape_string() expects exactly 2 parameters, 1 given in /var/whitecde/wp-config.php on line 2

I believe it is causing other problems with my website like I am unable to update any plugin or theme.

PS: I used this function:
function mysql_escape_string($string){return mysqli_escape_string($string);}