code: def fmt_bytes(bytes, precision=2):
      
      UNITS = ['bytes', 'KB', 'MB', 'GB', 'TB', 'PB']
  
      if bytes == 0:
          return '0 bytes'
  
      log = math.floor(math.log(bytes, 1000))
  
      return "%.*f %s" % (precision,
                         bytes / math.pow(1000, log),
                         UNITS[int(log)])
docs: Reduce a large number of `bytes` down to a humanised SI 
      equivalent and return the result as a string with trailing unit 
      abbreviation.