Fix custom component index function

src/backend/langflow/interface/custom/component.py

@@ -5,6 +5,7 @@ from typing import Any, ClassVar, Optional
 
 from cachetools import TTLCache, cachedmethod
 from fastapi import HTTPException
+
 from langflow.interface.custom.code_parser import CodeParser
 from langflow.utils import validate
 

src/backend/langflow/interface/custom/custom_component.py

@@ -197,7 +197,6 @@ class CustomComponent(Component):
 
         return get_credential
 
-    @property
     def list_key_names(self):
         if hasattr(self, "_user_id") and not self._user_id:
             raise ValueError(f"User id is not set for {self.__class__.__name__}")
@@ -206,6 +205,16 @@ class CustomComponent(Component):
         with session_getter(db_service) as session:
             return credential_service.list_credentials(user_id=self._user_id, session=session)
 
+    def index(self, value: int = 0):
+        """Returns a function that returns the value at the given index in the iterable."""
+
+        def get_index(iterable: List[Any]):
+            if iterable:
+                return iterable[value]
+            return iterable
+
+        return get_index
+
     @property
     def get_function(self):
         return validate.create_function(self.code, self.function_entrypoint_name)