refactor: decouple Node and NodeData (#22581)

Signed-off-by: -LAN- <laipz8200@outlook.com>
Co-authored-by: QuantumGhost <obelisk.reg+git@gmail.com>

api/core/prompt/simple_prompt_transform.py

@@ -29,19 +29,6 @@ class ModelMode(enum.StrEnum):
     COMPLETION = "completion"
     CHAT = "chat"
 
-    @classmethod
-    def value_of(cls, value: str) -> "ModelMode":
-        """
-        Get value of given mode.
-
-        :param value: mode value
-        :return: mode
-        """
-        for mode in cls:
-            if mode.value == value:
-                return mode
-        raise ValueError(f"invalid mode value {value}")
-
 
 prompt_file_contents: dict[str, Any] = {}
 
@@ -65,7 +52,7 @@ class SimplePromptTransform(PromptTransform):
     ) -> tuple[list[PromptMessage], Optional[list[str]]]:
         inputs = {key: str(value) for key, value in inputs.items()}
 
-        model_mode = ModelMode.value_of(model_config.mode)
+        model_mode = ModelMode(model_config.mode)
         if model_mode == ModelMode.CHAT:
             prompt_messages, stops = self._get_chat_model_prompt_messages(
                 app_mode=app_mode,