code: def test_librosa_stft():
      mkl_is_available = torch.backends.mkl.is_available()
      if not mkl_is_available:
          raise RuntimeError("MKL is not available.")
  
      layer = Stft()
      layer.eval()
      x = torch.randn(2, 16000, device="cpu")
      y_torch, _ = layer(x)
      torch._C.has_mkl = False
      y_librosa, _ = layer(x)
      assert torch.allclose(y_torch, y_librosa, atol=7e-6)
      torch._C.has_mkl = True
  
imports: import torch
  from espnet2.layers.stft import Stft
label_desc: Use image node_id 6 for calling a global function with example usage: test_librosa_stft() without return types