code: def _np_frame(data, window_length, hop_length):
      num_frames = 1 + int(
          np.floor((len(data) - window_length) // hop_length)
      )
      shape = (num_frames, window_length)
      strides = (data.strides[0] * hop_length, data.strides[0])
      return np.lib.stride_tricks.as_strided(
          data, shape=shape, strides=strides
      )
  
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 2 for calling the SpectralOpsTest obj's underlying member method code with example usage: obj._np_frame(data, window_length, hop_length) and returns: np