Don't raise error for partial functions

modal/app.py

@@ -537,24 +537,6 @@ def wrapped(
                     "The `@app.function` decorator cannot be used on a class. Please use `@app.cls` instead."
                 )
 
-            if not is_top_level_function(f) and not serialized:
-                raise InvalidError(
-                    dedent(
-                        """
-                    The `@app.function` decorator cannot be used on class methods.
-                    Please use `@app.cls` with `@modal.method` instead. Example:
-
-                    ```python
-                    @app.cls()
-                    class MyClass:
-                        @method()
-                        def f(self, x):
-                            ...
-                    ```
-                    """
-                    )
-                )
-
             if isinstance(f, _PartialFunction):
                 # typically for @function-wrapped @web_endpoint and @asgi_app
                 f.wrapped = True
@@ -571,6 +553,24 @@ def f(self, x):
                 webhook_config = None
                 raw_f = f
 
+                if not is_top_level_function(f) and not serialized:
+                    raise InvalidError(
+                        dedent(
+                            """
+                            The `@app.function` decorator cannot be used on class methods.
+                            Please use `@app.cls` with `@modal.method` instead. Example:
+
+                            ```python
+                            @app.cls()
+                            class MyClass:
+                                @method()
+                                def f(self, x):
+                                    ...
+                            ```
+                            """
+                        )
+                    )
+
             if info.function_name.endswith(".app"):
                 warnings.warn(
                     "Beware: the function name is `app`. Modal will soon rename `Stub` to `App`, "