// Exception should be caught and logged
                    exceptionHandled.set(true);
                }
            }
        };

        FwAssistantDirector assistantDirector = createMockAssistantDirector();
        customHook.hook(assistantDirector);

        // Verify that exception was handled
        assertTrue(exceptionHandled.get());
    }

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

And you want to handle this exception globally with FastAPI.

You could add a custom exception handler with `@app.exception_handler()`:

{* ../../docs_src/handling_errors/tutorial003.py hl[5:7,13:18,24] *}

Here, if you request `/unicorns/yolo`, the *path operation* will `raise` a `UnicornException`.