if ((lastConvSlot != null) &&
lastConvSlot.isInput() &&
lastConvSlot.getType().equals("number") &&
!topInputs.containsKey("lastConversation")) {
Conversation c = user.getLastConversation(id);
topTask.setSlotValue("lastConversation", c==null ? null : c.getStart());
}
if (Bool.isFalse(topTask.isApplicable()))
throw new IllegalArgumentException("task not applicable: " + topTask);