langchain[patch]: Extract _aperform_agent_action from _aiter_next_step from AgentExecutor (#15707)

- **Description:** extreact the _aperform_agent_action in the
AgentExecutor class to allow for easier overriding. Extracted logic from
_iter_next_step into a new method _perform_agent_action for consistency
and easier overriding.
- **Issue:** #15706

Closes #15706

libs/langchain/langchain/agents/agent.py

@@ -1179,6 +1179,17 @@ class AgentExecutor(Chain):
         for agent_action in actions:
             yield agent_action
         for agent_action in actions:
+            yield self._perform_agent_action(
+                name_to_tool_map, color_mapping, agent_action, run_manager
+            )
+
+    def _perform_agent_action(
+        self,
+        name_to_tool_map: Dict[str, BaseTool],
+        color_mapping: Dict[str, str],
+        agent_action: AgentAction,
+        run_manager: Optional[CallbackManagerForChainRun] = None,
+    ) -> AgentStep:
         if run_manager:
             run_manager.on_agent_action(agent_action, color="green")
         # Otherwise we lookup the tool
@@ -1209,7 +1220,7 @@ class AgentExecutor(Chain):
                 callbacks=run_manager.get_child() if run_manager else None,
                 **tool_run_kwargs,
             )
-            yield AgentStep(action=agent_action, observation=observation)
+        return AgentStep(action=agent_action, observation=observation)
 
     async def _atake_next_step(
         self,
@@ -1303,8 +1314,26 @@ class AgentExecutor(Chain):
         for agent_action in actions:
             yield agent_action
 
+        # Use asyncio.gather to run multiple tool.arun() calls concurrently
+        result = await asyncio.gather(
+            *[
+                self._aperform_agent_action(
+                    name_to_tool_map, color_mapping, agent_action, run_manager
+                )
+                for agent_action in actions
+            ],
+        )
+
+        # TODO This could yield each result as it becomes available
+        for chunk in result:
+            yield chunk
+
     async def _aperform_agent_action(
+        self,
+        name_to_tool_map: Dict[str, BaseTool],
+        color_mapping: Dict[str, str],
         agent_action: AgentAction,
+        run_manager: Optional[AsyncCallbackManagerForChainRun] = None,
     ) -> AgentStep:
         if run_manager:
             await run_manager.on_agent_action(
@@ -1340,15 +1369,6 @@ class AgentExecutor(Chain):
             )
         return AgentStep(action=agent_action, observation=observation)
 
-        # Use asyncio.gather to run multiple tool.arun() calls concurrently
-        result = await asyncio.gather(
-            *[_aperform_agent_action(agent_action) for agent_action in actions]
-        )
-
-        # TODO This could yield each result as it becomes available
-        for chunk in result:
-            yield chunk
-
     def _call(
         self,
         inputs: Dict[str, str],