_in_reply_to = get_in_reply_to(activity.data)
author = if with_author, do: [{:author, UserRepresenter.to_simple_form(user)}], else: []
_in_reply_to = get_in_reply_to(activity.data)
author = if with_author, do: [{:author, UserRepresenter.to_simple_form(user)}], else: []