'Start the tree from the requested children.'

def get_initial_candidates(self, comment_tree):

    children = [comment_id for comment_id in self.children if (comment_id in comment_tree.depth)]
    if children:
        children_depth = min((comment_tree.depth[comment_id] for comment_id in children))
        children = [comment_id for comment_id in children if (comment_tree.depth[comment_id] == children_depth)]
    initial_candidates = children
    offset_depth = 0
    return (initial_candidates, offset_depth)
