Return the list of tasks that can be submitted.
        Empty list if no task has been found.

def fetch_tasks_to_run(self):
        """
        Return the list of tasks that can be submitted.
        Empty list if no task has been found.
        """
        tasks_to_run = []

        for work in self.flow:
            tasks_to_run.extend(work.fetch_alltasks_to_run())

        return tasks_to_run