new_contents: from asyncio import coroutine
  
  import pytest
  
  
  @pytest.fixture
  def mocker(mocker):
      """
      Extend the global mocker fixture with a mock for coroutines.
  
      Args:
          mocker: Global mocker fixture as exported by pytest-mock.
  
      Returns:
          Modified mocker fixture that has an added `CoroMock` attribute.
      """
      def CoroMock(*args, **kwargs):
          coro = mocker.Mock(name="CoroutineResult", *args, **kwargs)
          corofunc = mocker.Mock(name="CoroutineFunction", side_effect=coroutine(coro))
          corofunc.coro = coro
          return corofunc
  
      mocker.CoroMock = CoroMock
      return mocker
  
subject: Add conftest with modified mocker fixture