Google Fonts: Poppins

Hello! I want to add a Google fonts. I’ve added the following code at the end of the functions.php but it doesn’t appear in the Fonts>Dropdown. What is wrong?

add_filter( ‘avf_google_heading_font’, ‘avia_add_heading_font’);
function avia_add_heading_font($fonts)
{
$fonts[‘Poppins’] = ‘Poppins:300,400,500,600,700’;
return $fonts;
}

add_filter( ‘avf_google_content_font’, ‘avia_add_content_font’);
function avia_add_content_font($fonts)
{
$fonts[‘Poppins’] = ‘Poppins:300,400,500,600,700’;
return $fonts;
}