diff --git a/curl_cffi/requests/session.py b/curl_cffi/requests/session.py
index 40c9201..51cc967 100644
--- a/curl_cffi/requests/session.py
+++ b/curl_cffi/requests/session.py
@@ -691,7 +691,7 @@ def __enter__(self):
     def __exit__(self, *args):
         self.close()
 
-    def close(self):
+    def close(self) -> None:
         """Close the session."""
         self._closed = True
         self.curl.close()
@@ -985,7 +985,7 @@ async def __aexit__(self, *args):
         await self.close()
         return None
 
-    async def close(self):
+    async def close(self) -> None:
         """Close the session."""
         await self.acurl.close()
         self._closed = True