feat(langflow): add function support to build_template_from_class function

feat(langflow): add function base class to InitializeAgentNode

The `build_template_from_class` function in `ChainCreator` now supports adding a function to the chain. This is done by passing `add_function=True` to the function.

In `InitializeAgentNode`, the `base_classes` attribute has been updated to include the `function` base class. This allows the node to be used as a function in the chain.

src/backend/langflow/interface/chains/base.py

@@ -37,7 +37,9 @@ class ChainCreator(LangChainTypeCreator):
         try:
             if name in get_custom_nodes(self.type_name).keys():
                 return get_custom_nodes(self.type_name)[name]
-            return build_template_from_class(name, self.type_to_loader_dict)
+            return build_template_from_class(
+                name, self.type_to_loader_dict, add_function=True
+            )
         except ValueError as exc:
             raise ValueError("Chain not found") from exc
         except AttributeError as exc:

src/backend/langflow/template/nodes.py

@@ -216,7 +216,7 @@ class InitializeAgentNode(FrontendNode):
         ],
     )
     description: str = """Construct a json agent from an LLM and tools."""
-    base_classes: list[str] = ["AgentExecutor"]
+    base_classes: list[str] = ["AgentExecutor", "function"]
 
     def to_dict(self):
         return super().to_dict()