get_collapsed_commnts in Client.pm

link_id is the ID of the link the comments are under.

children is a reference to an array containing the comment IDs.

If limit_children is true, return only the requested comments, not replies to them. Otherwise return as many replies as possible (possibly resulting in more MoreComments objects down the line).

sort is one of 'confidence', 'top', 'new', 'controversial', 'old', 'random', 'qa', 'live'. Default seems to be 'confidence'.