Decorator pipeline example using List

from typing import Callable, List

Define a callable type

First [None] indicates input argument for the callable function
Second None indicates output argument for the callable function

Pipeline_Step = Callable[[None], None]

Create a pipeline variable to hold a list of step
This list represents the collection of all the steps in the pipeline

pipeline: List[Pipeline_Step] = []

Create a function to register callables (i.e. functions) via a decorator

def register_step(step: Pipeline_Step) -> None:
    print(f"Added {step.__name__} to pipeline.")
    pipeline.append(step)

Decorate callables using the register_step function
The callable is added to the pipeline when the callable is defined

@register_step
def step_one() -> None:
    print("Inside Step 1")

Added step_one to pipeline.

@register_step
def step_two() -> None:
    print("Inside Step 2")

Added step_two to pipeline.

To execute all steps in the pipeline, simply loop thru the list and call each registered callable

for step in pipeline:
    step()

Inside Step 1
Inside Step 2