fix quotation mark

app.py

@@ -29,7 +29,7 @@ def historical_event_explorer(query :str, year: int = None)-> str: #it's import
         1923: "The Republic of Turkey was established.",
         1969: "Apollo 11 landed on the Moon.",
         "war": "Notable wars include WWI (1914-1918) and WWII (1939-1945).",
-        "invention": "Key inventions include the printing press (1440),
+        "invention": "Key inventions include the printing press (1440).",
     }
 
     # Check if the query mathces a year of keyword