Update app.py

app.py

@@ -239,7 +239,26 @@ into equivalent C# using a fine-tuned Qwen2.5-Coder model.
             user_input,
         ],
     )
-
+def _clean_csharp_output(code: str) -> str:
+    """
+    Remove spurious `virtual` / `override` modifiers the model adds to bare
+    (class-less) method snippets.
+
+    The model was trained on C# methods that usually live inside a class, where
+    `public virtual ...` is common. When it translates a *standalone* Java method
+    it carries the `virtual` keyword over — but `virtual`/`override` are only
+    valid on members of a class, so on a bare snippet they are invalid C#.
+    We therefore strip them ONLY when the snippet has no enclosing type
+    declaration (class / struct / interface / record / enum).
+    """
+    if re.search(r"\b(class|struct|interface|record|enum)\b", code):
+        return code  # real type present — leave modifiers intact
+    # Drop 'virtual'/'override' after an access modifier: 'public virtual int' -> 'public int'.
+    code = re.sub(r"\b(public|private|protected|internal)\s+(?:virtual|override)\s+",
+                  r"\1 ", code)
+    # Drop a leading 'virtual'/'override' with no access modifier.
+    code = re.sub(r"(^|\n)(\s*)(?:virtual|override)\s+", r"\1\2", code)
+    return code
 
 if __name__ == "__main__":
     demo.queue(