old_contents: import pytest
  
  from ratelimiter import RateLimiter
  
  @pytest.mark.asyncio
  async def test_alock():
      rl = RateLimiter(max_calls=10, period=0.01)
  
      assert rl._alock is None
  
      async with rl:
          pass
  
      alock = rl._alock
      assert alock
  
      async with rl:
          pass
  
      assert rl._alock is alock
  
new_contents: import pytest
  
  from ratelimiter import RateLimiter
  
  @pytest.mark.asyncio
  async def test_alock(event_loop):
      rl = RateLimiter(max_calls=10, period=0.01)
  
      assert rl._alock is None
  
      async with rl:
          pass
  
      alock = rl._alock
      assert alock
  
      async with rl:
          pass
  
      assert rl._alock is alock
  
subject: Fix Runtime warnings on async tests