text: Title: How to import evaluate_cy?
  Body: try:
      from torchreid.metrics.rank_cylib.rank_cy import evaluate_cy
      IS_CYTHON_AVAI = True
  except ImportError:
      IS_CYTHON_AVAI = False
      warnings.warn(
          'Cython evaluation (very fast so highly recommended) is '
          'unavailable, now use python evaluation.'
      )