Need help with concurrent task:

Mojo
1

I failed to create a concurrent task that takes 2 parameters and return a value. Can anyone help?

async fn task1(a: Int, b: String) -> List [UInt256]:
    return []

fn main() raises:        
    var tg = TaskGroup()
    tg.create_task(task1(1, "Hi"))
    tg.wait()

error: invalid call to 'create_task': failed to infer implicit parameter 'origins' of argument 'task' type 'Coroutine'
    tg.create_task(task1(1, "Hi"))
    ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
2

async in Mojo is not currently in a usable state. The syntax works, but there are many, many, many things which do not work properly.