from typing import List, Optional

import typer


def main(device: Optional[List[str]] = typer.Option(None)):
    if not device:
        print("No provided devices")
        raise typer.Abort()
    for d in device:
        print(f"Processing device: {d}")


if __name__ == "__main__":
    typer.run(main)

And then it can be used like in:

$ ./my_cli --device 1 --device 2

Take a look at the documentation.

If the only input for the CLI is a list of devices, you can simplify it to using arguments instead. Then it could be used like:

$ ./my_cli 1 2

Just had to use inverted commas around description (here "Clean House") for it to consider spaces. feels so silly now.

C:\Users\Asus\Desktop\fellowship-python\python>.\task add 10 "Clean House"
('Clean House',)
Added task: "Clean House" with priority 10

I went through many iterations before I figured it out. In banana.py:

from typing import List, Optional
import docker
import typer
from typing_extensions import Annotated

@app.callback(invoke_without_command=True)
def main(commands: Annotated[Optional[List[str]], typer.Argument()] = None) -> None:
    # run the banana command with all arguments
    client = docker.from_env()
    client.containers.run(image, commands)

The above code (fully typed!) means I can run commands like the following:

mycli banana
mycli banana arg1
mycli banana arg1 arg2 arg3

and it all works as expected!

Suggestions for improvement would be greatly appreciated.

NB. This question is similar to this one but is not quite the same. And this issue was helpful too.