def _get_window_sizes(num_adaptation_steps):
  """Hardcoded way to get a reasonable scheme.

  This assumes we do something proportional to

  fast window: 75 steps
  slow window: 25 steps
  slow window: 50 steps
  slow window: 100 steps
  slow window: 200 steps
  fast window: 50 steps

  Which is a total of 500 steps.

  Args:
    num_adaptation_steps: int Number of adaptation steps to run.

  Returns:
    The first window size, the initial slow window size, the last window size.
  """
  slow_window_size = num_adaptation_steps // 20
  first_window_size = 3 * slow_window_size
  last_window_size = (num_adaptation_steps -
                      15 * slow_window_size -
                      first_window_size)
  return first_window_size, slow_window_size, last_window_size