Daniel Arbuckle's Mastering Python

ensure_future

We can also override default scheduler by passing an explicit event_loop scheduler to the loop keyword-only parameter of the ensure_future function.

f = asyncio.ensure_future(coroutine.example(),  loop = scheduler)

Notice that we didn't just pass the coroutine function to ensure_future; we actually invoked it right there inside ensure_future arguments. We did this because the ensure_future function doesn't actually want to refer to the coroutine function. The ensure_future function is only interested in the coroutine object that we saw the coroutine function return earlier. The name ensure_future might seem somewhat odd. If it's used for launching tasks, why is it called that?

The fact of the matter is that launching tasks ...