+ * Returns the reply with the given ID. If there is no reply with the given
+ * ID yet, a new one is created, unless {@code create} is false in which
+ * case {@code null} is returned.
+ *
+ * @param replyId
+ * The ID of the reply to get
+ * @param create
+ * {@code true} to always return a {@link Reply}, {@code false}
+ * to return {@code null} if no reply can be found
+ * @return The reply, or {@code null} if there is no such reply