Several "build tasks" for visual studio code (python)

My tasks.json looks like this:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    // A task runner that runs a python program
    "command": "python3",
    "presentation": {
        "echo": true,
        "reveal": "always",
        "focus": true
    },
    "args": [
        "${file}"
    ]
}

When I run ctrl+shift+B the top panel asks "Select the build task to run", and there's one alternative: python3. Now if I'd like to add a new build-task (for example a runspider command with scrapy), so it's added to the build tasks. How would I go about adding this?