How to get the number of posts in the OK group?

Question

Classmates

I wrote to the Odnoklassniki TP, they said to use the mediatopic.getTopics method to get the number of posts in the group. As soon as I did not play with this method - it returns only the number of topics in the group, but not as posts.
An example of my parameters for this method:

call('mediatopic.getTopics', {
    filter: 'GROUP_THEMES',
    gid: source.id,
    count: 10
}, function(info) {
    console.log(info);
});