code: def strsize (b):
      
      if b < 0:
          raise ValueError("Invalid negative byte number")
      if b < 1024:
          return "%dB" % b
      if b < 1024 * 10:
          return "%dKB" % (b // 1024)
      if b < 1024 * 1024:
          return "%.2fKB" % (float(b) / 1024)
      if b < 1024 * 1024 * 10:
          return "%.2fMB" % (float(b) / (1024*1024))
      if b < 1024 * 1024 * 1024:
          return "%.1fMB" % (float(b) / (1024*1024))
      if b < 1024 * 1024 * 1024 * 10:
          return "%.2fGB" % (float(b) / (1024*1024*1024))
      return "%.1fGB" % (float(b) / (1024*1024*1024))
docs: Return human representation of bytes b. A negative number of bytes
      raises a value error.