refactor base scoring fn v.s. registerable scoring fn

llama_stack/providers/utils/scoring/base_scoring_fn.py

@@ -13,12 +13,51 @@ from llama_stack.providers.utils.scoring.aggregation_utils import aggregate_metr
 
 class BaseScoringFn(ABC):
     """
-    Base interface class for all native scoring_fns.
-    Each scoring_fn needs to implement the following methods:
+    Base interface class for Scoring Functions.
+    Each scoring function needs to implement the following methods:
     - score_row(self, row)
     - aggregate(self, scoring_fn_results)
     """
 
+    def __init__(self, *args, **kwargs) -> None:
+        super().__init__(*args, **kwargs)
+
+    def __str__(self) -> str:
+        return self.__class__.__name__
+
+    @abstractmethod
+    async def score_row(
+        self,
+        input_row: Dict[str, Any],
+        scoring_fn_identifier: Optional[str] = None,
+        scoring_params: Optional[ScoringFnParams] = None,
+    ) -> ScoringResultRow:
+        raise NotImplementedError()
+
+    @abstractmethod
+    async def aggregate(
+        self,
+        scoring_results: List[ScoringResultRow],
+        scoring_fn_identifier: Optional[str] = None,
+        scoring_params: Optional[ScoringFnParams] = None,
+    ) -> Dict[str, Any]:
+        raise NotImplementedError()
+
+    @abstractmethod
+    async def score(
+        self,
+        input_rows: List[Dict[str, Any]],
+        scoring_fn_identifier: Optional[str] = None,
+        scoring_params: Optional[ScoringFnParams] = None,
+    ) -> List[ScoringResultRow]:
+        raise NotImplementedError()
+
+
+class RegisteredBaseScoringFn(BaseScoringFn):
+    """
+    Interface for native scoring functions that are registered in LlamaStack.
+    """
+
     def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
         self.supported_fn_defs_registry = {}