code: def contrast(
      waveform: Tensor, enhancement_amount: float = 75.0
  ) -> Tensor:
      r"""Apply contrast effect.  Similar to SoX implementation.
  
      .. devices:: CPU CUDA
  
      .. properties:: Autograd TorchScript
  
      Comparable with compression, this effect modifies an audio signal to make it sound louder
  
      Args:
          waveform (Tensor): audio waveform of dimension of `(..., time)`
          enhancement_amount (float, optional): controls the amount of the enhancement
              Allowed range of values for enhancement_amount : 0-100
              Note that enhancement_amount = 0 still gives a significant contrast enhancement
  
      Returns:
          Tensor: Waveform of dimension of `(..., time)`
  
      Reference:
          - http://sox.sourceforge.net/sox.html
      """
  
      if not 0 <= enhancement_amount <= 100:
          raise ValueError(
              "Allowed range of values for enhancement_amount : 0-100"
          )
  
      contrast = enhancement_amount / 750.0
  
      temp1 = waveform * (math.pi / 2)
      temp2 = contrast * torch.sin(temp1 * 4)
      output_waveform = torch.sin(temp1 + temp2)
  
      return output_waveform
  
imports: import math
  import warnings
  from typing import Optional
  import torch
  from torch import Tensor
  from torchaudio._extension import _IS_TORCHAUDIO_EXT_AVAILABLE
label_desc: Use image node_id 9 for calling a global function with example usage: contrast(waveform, enhancement_amount) and returns: output_waveform