Added decorator pattern and unit tests for add_task.

[iodone]

We can add tasks like this:

    @flow.task("decorated_task")
    def action(ctx) -> TaskOutput:
        return TaskOutput("result")

    result = flow.run("decorated_task")

@skull8888888 Do you think this approach is feasible?

[skull8888888]

@iodone decorator is a good suggestion, although I am a bit worried that it might cause confusion on what to use, add_task or @flow.task? I'm not sure tho, what are your thoughts?

Initial reason for .add_task was to be able to import function from another files.

[iodone]

@iodone decorator is a good suggestion, although I am a bit worried that it might cause confusion on what to use, add_task or @flow.task? I'm not sure tho, what are your thoughts?
Initial reason for.add_task was to be able to import function from another files.

IMO, both can be supported. The decorator pattern is mainly to use a declarative way to plan the entire flow at once, which is user-friendly.