func IsARMBFX(op obj.As) bool {
	switch op {
	case arm.ABFX, arm.ABFXU, arm.ABFC, arm.ABFI:
		return true
	}
	return false
}

// IsARMFloatCmp reports whether the op is a floating comparison instruction.
func IsARMFloatCmp(op obj.As) bool {
	switch op {
	case arm.ACMPF, arm.ACMPD:
		return true
	}
	return false
}

We create an async function `lifespan()` with `yield` like this:

```Python hl_lines="16  19"
{!../../../docs_src/events/tutorial003.py!}
```

Here we are simulating the expensive *startup* operation of loading the model by putting the (fake) model function in the dictionary with machine learning models before the `yield`. This code will be executed **before** the application **starts taking requests**, during the *startup*.