docs: add async prefix for async fn define (#68)

diff --git a/docs/src/en/sdk/python.md b/docs/src/en/sdk/python.md
index c016ac6..927ca7a 100644
--- a/docs/src/en/sdk/python.md
+++ b/docs/src/en/sdk/python.md
@@ -60,7 +60,7 @@
 Here is a example for creating table by the initialized client:
 
 ```python
-def async_query(client, ctx, req):
+async def async_query(client, ctx, req):
     await client.sql_query(ctx, req)
 
 create_table_sql = 'CREATE TABLE IF NOT EXISTS demo ( \