docs: def mcs_to_rate(mcs, bw=20, long_gi=True):
      """Convert MCS index to rate in Mbps.
  
      See http://mcsindex.com/
  
      Args:
          mcs (int): MCS index
          bw (int): bandwidth, 20, 40, 80, ...
          long_gi(bool): True if long GI is used.
  
      Returns:
          rate (float): bitrate in Mbps
  
  
      >>> mcs_to_rate(5, bw=20, long_gi=False)
      57.8
  
      >>> mcs_to_rate(4, bw=40, long_gi=True)
      81
  
      >>> mcs_to_rate(3, bw=80, long_gi=False)
      130
  
      >>> mcs_to_rate(13, bw=160, long_gi=True)
      936
      """
      if bw not in [20, 40, 80, 160]:
          raise Exception("Unknown bandwidth: %d MHz" % (bw))
      if mcs not in MCS_TABLE:
          raise Exception("Unknown MCS: %d" % (mcs))
  
      idx = int((math.log(bw/10, 2)-1)*2)
      if not long_gi:
          idx += 1
      return MCS_TABLE[mcs][idx]