Google Fonts – Old Standard TT

well yes, i’ve read this before i wrote this ticket. It feels a little stupid, but i don’t know what to type down in the function.php
Probably i write something wrong, or i have to define something else. I am sorry, but i don’t have a clou.

I use the plugin “Code Snippets” for the reason, that i don’t have to code in the function.php
Code Snippets works well, but with this code i don’t get the fonts.

add_filter( ‘avf_google_heading_font’, ‘avia_add_heading_font’);
function avia_add_heading_font($fonts)
{
$fonts[‘Old Std. TT’] = ‘Old Standard TT’;
return $fonts;
}

add_filter( ‘avf_google_content_font’, ‘avia_add_content_font’);
function avia_add_content_font($fonts)
{

$fonts[‘Old Std. TT’] = ‘Old Standard TT’;
return $fonts;
}

of course, here are the details.
you have every permission