code: def test_backoff_time() -> None:
      backend = Backoff(
          backend=FailArtifactStore(),
          min_delay=0.1,
          multiplier=10,
          max_delay=10,
      )
      assert backend._get_sleep_secs(0) == 0.1
      assert backend._get_sleep_secs(1) == 1
      assert backend._get_sleep_secs(2) == 10
  
imports: import io
  import uuid
  from optuna.artifacts import Backoff
  from .stubs import FailArtifactStore
  from .stubs import InMemoryArtifactStore
label_desc: Use image node_id 1 for calling a global function with example usage: test_backoff_time() without return types