code: def get_noise_level(cell):
      
  
      noise = matching_line(cell, "Noise level=")
      if noise is None:
          return ""
      noise = noise.split("=")[1]
      return noise.split(' ')[0]
docs: Gets the noise level of a network / cell.
      @param string cell
          A network / cell from iwlist scan.
  
      @return string
          The noise level of the network.