Fix: Optimize edge check & incorrect parameter usage (#11396)

### What problem does this PR solve?

Fix: incorrect parameter usage #8084
Fix: Optimize edge check #10851

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

sdk/python/ragflow_sdk/modules/document.py

@@ -69,7 +69,7 @@ class Document(Base):
             response = res.json()
             actual_keys = set(response.keys())
             if actual_keys == error_keys:
-                raise Exception(res.get("message"))
+                raise Exception(response.get("message"))
             else:
                 return res.content
         except json.JSONDecodeError:

sdk/python/ragflow_sdk/modules/session.py

@@ -80,6 +80,7 @@ class Session(Base):
         
 
     def _structure_answer(self, json_data):
+        answer = ""
         if self.__session_type == "agent":
            answer = json_data["data"]["content"]
         elif self.__session_type == "chat":