docs: def _growing_step_sequence(interval_growth, max_interval, init_interval, start_level=None):
          """
          Returns an iterator that constructs a sequence of trigger levels with growing intervals.
          The interval is growing exponentially until it reaches the maximum value. Then the interval
          stays the same and the sequence becomes linear.
  
          An optional starting level `start_level` defaults to the initial interval. The interval
          starts out as `init_interval`, multiplied by `interval_growth` in each step until it
          reaches the `max_interval`.
          """
          interval = init_interval
          next_level = start_level or init_interval
          while True:
              yield next_level
              interval = min(interval * interval_growth, max_interval)
              next_level += interval