@@ -725,7 +725,7 @@
     {
      "data": {
       "text/plain": [
-       "[['to be', '20250315H165549399269jJTGt6qBto be20250315H165549399295XtRgNy0I'],\n",
+       "[['to be', '20250316H062020000663jJTGt6qBto be20250316H062020000683XtRgNy0I'],\n",
        " [6, 10],\n",
        " [0.6118970848141451, 1.928063278403899]]"
       ]
@@ -2982,7 +2982,9 @@
     "        current = self.negotiators[nxt]\n",
     "        offer = None\n",
     "        self.state.current_offer = (\n",
-    "            current.propose(self.state) if offer is None else offer\n",
+    "            current.propose(self.state, self.current_offerer)\n",
+    "            if offer is None\n",
+    "            else offer\n",
     "        )\n",
     "\n",
     "        def get_response(negotiator, state=self.state):\n",
 
@@ -261,11 +261,11 @@
     "This is telling us that there is one (and only one) required abstract method that we need to override called `propose()`. This is the signature of this method:\n",
     "\n",
     "```python\n",
-    "def proposed(self, state: SAOState) -> Outcome:\n",
+    "def propose(self, state: SAOState, dest: str | None = None) -> Outcome:\n",
     "    ...\n",
     "```\n",
     "\n",
-    "It receives the negotiation `state` which has all information available to the negotiator about the current state of the negotiation and generates an outcome to *offer* to the opponent. That is it. Moreover, we should know that the negotiator always have access to a `NegotiatorMechanismInterface` object that gives it unchanging information about the negotiation (for example the number of allowed rounds, any real-time limits on the negotiation, the number of partners, etc). This interface is accessible through the `nmi` member of the negotiator. With this knowledge,  we can build our first negotiator which will simply offer randomly. "
+    "It receives the negotiation `state` which has all information available to the negotiator about the current state of the negotiation and generates an outcome to *offer* to the opponent. The second parameter (which MUST be optional) is the destination of the offer. That is it. Moreover, we should know that the negotiator always have access to a `NegotiatorMechanismInterface` object that gives it unchanging information about the negotiation (for example the number of allowed rounds, any real-time limits on the negotiation, the number of partners, etc). This interface is accessible through the `nmi` member of the negotiator. With this knowledge,  we can build our first negotiator which will simply offer randomly. "
    ]
   },
   {
@@ -606,7 +606,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 25,
    "id": "3b66d1c6",
    "metadata": {
     "papermill": {
@@ -621,7 +621,7 @@
    "outputs": [],
    "source": [
     "class BetterRandomNegotiator(RandomNegotiator):\n",
-    "    def respond(self, state, source: str = \"\"):\n",
+    "    def respond(self, state, source: str | None = None):\n",
     "        offer = state.current_offer\n",
     "        if self.ufun(offer) > 0.9:\n",
     "            return ResponseType.ACCEPT_OFFER\n",
@@ -905,7 +905,8 @@
     "        super().__init__(*args, **kwargs)\n",
     "        self._th = acceptance_threshold\n",
     "\n",
-    "    def respond(self, state, offer, nid: str):\n",
+    "    def respond(self, state, source: str | None = None):\n",
+    "        offer = state.current_offer\n",
     "        if self.ufun(offer) > self._th:\n",
     "            return ResponseType.ACCEPT_OFFER\n",
     "        return ResponseType.REJECT_OFFER"
@@ -985,7 +986,7 @@
     "        # MUST call parent to avoid being called again for no reason\n",
     "        super().on_preferences_changed(changes)\n",
     "\n",
-    "    def respond(self, state, source: str):\n",
+    "    def respond(self, state, source: str | None = None):\n",
     "        offer = state.current_offer\n",
     "        if offer is None:\n",
     "            return ResponseType.REJECT_OFFER\n",