docstr: Computes the gradient of the STFT with respect to `signal`.
docstr_tok: ["Computes","the","gradient","of","the","STFT","with","respect","to","`","signal","`","."]
code: def _compute_stft_gradient(
      signal, frame_length=32, frame_step=16, fft_length=32
  ):
      """Computes the gradient of the STFT with respect to `signal`."""
      stft = spectral_ops.stft(
          signal, frame_length, frame_step, fft_length
      )
      magnitude_stft = math_ops.abs(stft)
      loss = math_ops.reduce_sum(magnitude_stft)
      return gradients_impl.gradients([loss], [signal])[0]
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.eager import context
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops.signal import spectral_ops
  from tensorflow.python.ops.signal import window_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 12 for calling the SpectralOpsTest obj's underlying member method code with example usage: obj._compute_stft_gradient(signal, frame_length, frame_step, fft_length) and returns: gradients_impl