code: def expected_f0_length(self, audio, padding):
      n_t = audio.shape[-1]
      frame_size = spectral_ops.CREPE_FRAME_SIZE
      hop_size = int(16000 // self.frame_rate)
      expected_len, _ = spectral_ops.get_framed_lengths(
          n_t, frame_size, hop_size, padding
      )
      return expected_len
  
imports: from absl.testing import parameterized
  from ddsp import spectral_ops
  from ddsp.test_util import gen_np_sinusoid
  import numpy
  import tensorflow.compat.v2
label_desc: Use image node_id 2 for calling the ComputeFeaturesTest obj's underlying member method code with example usage: obj.expected_f0_length(audio, padding) and returns: expected_len