Error handling

import time
from learning_commons_evaluators import EvaluatorError, RateLimitError

for attempt in range(3):
  try:
    result = evaluator.evaluate_sync(input)
    break
  except EvaluatorError as e:
    # Every EvaluatorError exposes a boolean retryable attribute
    if not e.retryable or attempt == 2:
      raise
    delay = e.retry_after if isinstance(e, RateLimitError) and e.retry_after else 2 ** attempt # retry_after is in seconds
    time.sleep(delay)