Add sdk for list agents and sessions (#3848)

### What problem does this PR solve?

Add sdk for list agents and sessions

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

sdk/python/ragflow_sdk/modules/agent.py

@@ -1,6 +1,7 @@
 from .base import Base
 from .session import Session
 import requests
+from typing import List
 
 class Agent(Base):
     def __init__(self,rag,res_dict):
@@ -57,3 +58,18 @@ class Agent(Base):
             return Session(rag,res.get("data"))
         raise Exception(res.get("message"))
 
+    @staticmethod
+    def list_sessions(agent_id,rag,page: int = 1, page_size: int = 30, orderby: str = "create_time", desc: bool = True,
+                      id: str = None) -> List[Session]:
+        url = f"{rag.api_url}/agents/{agent_id}/sessions"
+        headers = {"Authorization": f"Bearer {rag.user_key}"}
+        params = {"page": page, "page_size": page_size, "orderby": orderby, "desc": desc, "id": id}
+        res = requests.get(url=url,headers=headers,params=params)
+        res = res.json()
+        if res.get("code") == 0:
+            result_list = []
+            for data in res.get("data"):
+                temp_agent = Session(rag,data)
+                result_list.append(temp_agent)
+            return result_list
+        raise Exception(res.get("message"))

sdk/python/ragflow_sdk/modules/session.py

@@ -8,12 +8,12 @@ class Session(Base):
         self.id = None
         self.name = "New session"
         self.messages = [{"role": "assistant", "content": "Hi! I am your assistant，can I help you?"}]
-        self.chat_id = None
-        self.agent_id = None
         for key,value in res_dict.items():
             if key =="chat_id" and value is not None:
+                self.chat_id = None
                 self.__session_type = "chat"
             if key == "agent_id" and value is not None:
+                self.agent_id = None
                 self.__session_type = "agent"
         super().__init__(rag, res_dict)