diff --git a/src/server.py b/src/server.py
index c4b8fa3..0d0b1a6 100644
--- a/src/server.py
+++ b/src/server.py
@@ -6,33 +6,40 @@ import sqlite3
 import asyncio
 import time
 
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     init()
     yield
     clean_env()
 
-app = FastAPI(lifespan = lifespan)
+
+app = FastAPI(lifespan=lifespan)
 
 # 连接到数据库（如果数据库不存在，则会自动创建）
-conn = sqlite3.connect('server.db')
+conn = sqlite3.connect("server.db")
 # 创建游标对象，用于执行SQL语句
 cursor = conn.cursor()
 # 创建表: id: int; ip: TEXT
-cursor.execute('''CREATE TABLE IF NOT EXISTS nodes (
+cursor.execute(
+    """CREATE TABLE IF NOT EXISTS nodes (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    ip TEXT NOT NULL,
                    last_heartbeat INTEGER
-               )''')
+               )"""
+)
+
 
 def init():
     asyncio.create_task(receive_heartbeat_internal())
 
+
 def clean_env():
     # 关闭游标和连接
     cursor.close()
     conn.close()
 
+
 @app.get("/server/show_nodes")
 async def show_nodes() -> list:
     nodes_list = []
@@ -43,37 +50,42 @@ async def show_nodes() -> list:
         nodes_list.append(row)
     return nodes_list
 
+
 @app.get("/server/get_node")
 async def get_node(ip: str) -> int:
-    '''
-    中心服务器与节点交互, 节点发送ip, 中心服务器接收ip存入数据库并将ip转换为int作为节点id返回给节点  
-    params:  
-    ip: node ip  
-    return:  
-    id: ip按点分割成四部分, 每部分转二进制后拼接再转十进制作为节点id  
-    '''
+    """
+    中心服务器与节点交互, 节点发送ip, 中心服务器接收ip存入数据库并将ip转换为int作为节点id返回给节点
+    params:
+    ip: node ip
+    return:
+    id: ip按点分割成四部分, 每部分转二进制后拼接再转十进制作为节点id
+    """
     ip_parts = ip.split(".")
     ip_int = 0
     for i in range(4):
         ip_int += int(ip_parts[i]) << (24 - (8 * i))
-    
+
     # 获取当前时间
     current_time = int(time.time())
 
     # 插入数据
-    cursor.execute("INSERT INTO nodes (id, ip, last_heartbeat) VALUES (?, ?, ?)", (ip_int, ip, current_time))
+    cursor.execute(
+        "INSERT INTO nodes (id, ip, last_heartbeat) VALUES (?, ?, ?)",
+        (ip_int, ip, current_time),
+    )
     conn.commit()
 
     return ip_int
 
+
 @app.get("/server/delete_node")
 async def delete_node(ip: str) -> None:
-    '''
+    """
     param:
     ip: 待删除节点的ip地址
     return:
     None
-    '''
+    """
     # 查询要删除的节点
     cursor.execute("SELECT * FROM nodes WHERE ip=?", (ip,))
     row = cursor.fetchone()
@@ -85,12 +97,16 @@ async def delete_node(ip: str) -> None:
     else:
         print(f"Node with IP {ip} not found.")
 
+
 # 接收节点心跳包
 @app.post("/server/heartbeat")
 async def receive_heartbeat(ip: str):
-        cursor.execute("UPDATE nodes SET last_heartbeat = ? WHERE ip = ?", (time.time(), ip))
-        return {"status": "received"}     
-    
+    cursor.execute(
+        "UPDATE nodes SET last_heartbeat = ? WHERE ip = ?", (time.time(), ip)
+    )
+    return {"status": "received"}
+
+
 async def receive_heartbeat_internal():
     while 1:
         timeout = 70
@@ -99,33 +115,35 @@ async def receive_heartbeat_internal():
         # conn.commit()
         await asyncio.sleep(timeout)
 
+
 @app.get("/server/send_nodes_list")
 async def send_nodes_list(count: int) -> list:
-    '''
+    """
     中心服务器与客户端交互, 客户端发送所需节点个数, 中心服务器从数据库中顺序取出节点封装成list格式返回给客户端
-    params:  
-    count: 所需节点个数  
-    return:  
+    params:
+    count: 所需节点个数
+    return:
     nodes_list: list
-    '''
+    """
     nodes_list = []
 
     # 查询数据库中的节点数据
     cursor.execute("SELECT * FROM nodes LIMIT ?", (count,))
     rows = cursor.fetchall()
-
     for row in rows:
         id, ip, last_heartbeat = row
         nodes_list.append(ip)
 
     return nodes_list
 
+
 @app.get("/server/clear_database")
 async def clear_database() -> None:
     cursor.execute("DELETE FROM nodes")
     conn.commit()
 
+
 if __name__ == "__main__":
     import uvicorn  # pylint: disable=e0401
 
-    uvicorn.run("server:app", host="0.0.0.0", port=8000, reload=True)
\ No newline at end of file
+    uvicorn.run("server:app", host="0.0.0.0", port=8000, reload=True)