code: def zeroing(dev):
      
      # this kills the crab
      #
      # sgdisk will wipe out the main copy of the GPT partition
      # table (sorry), but it doesn't remove the backup copies, and
      # subsequent commands will continue to complain and fail when
      # they see those.  zeroing the last few blocks of the device
      # appears to do the trick.
      lba_size = 4096
      size = 33 * lba_size
      return True
      with open(dev, 'wb') as f:
          f.seek(-size, os.SEEK_END)
          f.write(size*b'\0')
docs: zeroing last few blocks of device