allow looping with conditionals

[mt-ob]

from metaflow import FlowSpec, step

class LoopingFlow(FlowSpec):
    @step
    def start(self):
        print("Flow starting. Initializing loop counter.")
        # This variable will track our position in the loop.
        self.count = 0
        # We will loop 5 times.
        self.max_iterations = 5
        self.next(self.loop_step)

    @step
    def loop_step(self):
        print(f"Executing loop iteration number: {self.count}")
        self.count += 1
        self.loop_status = 'continue' if self.count < self.max_iterations else 'exit'
        print(f"Loop status is '{self.loop_status}'. Deciding next step...")
        self.next(
            {
                'continue': self.loop_step,
                'exit': self.exit_loop
            },
            condition='loop_status'
        )

    @step
    def exit_loop(self):
        print(f"Loop finished after {self.count} iterations.")
        self.next(self.end)

    @step
    def end(self):
        print("Flow has finished successfully.")

if __name__ == '__main__':
    LoopingFlow()