Update app.py

app.py

@@ -21,15 +21,18 @@ def my_custom_tool(arg1:str, arg2:int)-> str: #it's import to specify the return
     Returns:
         The ciphered string after performing a rotX transformation.
     """
-    def rotate_char(c: str, shift: int) -> str:
-        if 'a' <= c <= 'z':
-            return chr((ord(c) - ord('a') + shift) % 26 + ord('a'))
-        elif 'A' <= c <= 'Z':
-            return chr((ord(c) - ord('A') + shift) % 26 + ord('A'))
-        else:
-            return c
+    if arg2 is None:
+        raise ValueError("arg2 must be an integer, not None")
 
-    return "".join(rotate_char(c, arg2) for c in arg1)
+    result = []
+    for char in arg1:
+        if char.isalpha():
+            base = ord('A') if char.isupper() else ord('a')
+            rotated = chr((ord(char) - base + arg2) % 26 + base)
+            result.append(rotated)
+        else:
+            result.append(char)
+    return ''.join(result)
 
 
 @tool