Update app.py

app.py

@@ -18,7 +18,8 @@ def replace_vowels_with_x_and_concatenate_with_provided_int(sentence:str, number
         number: the second argument
     """
     vowels = "aeiouAEIOU"
-    result += ''.join('X' if char in vowels else char for char in sentence)+result
+    result = ""
+    result = ''.join('X' if char in vowels else char for char in sentence)+result
     return f"Here's the output of your function: '{result}'"
 
 @tool