code: def _get_ratio(mat):
      return (mat.sum() / mat.numel()).item()
  
imports: import torch
  import torchaudio.prototype.transforms
  from torchaudio_unittest.common_utils import get_spectrogram, get_whitenoise, TestBaseMixin
label_desc: Use image node_id 1 for calling a global function with example usage: _get_ratio(mat) and returns: unknown