Update app.py

app.py

@@ -16,7 +16,7 @@ def fahrenheit_to_celsius(temperature:str)-> str: #it's import to specify the re
     Args:
         temperature: The current temperature.
     """
-    is_fahrenheit = temperature.split("°F").[0]
+    is_fahrenheit = temperature.split("°F")[0]
     if is_fahrenheit == "°F":
         temperature = (temperature - 32) * 5/9