def _DiskSize(value):
  """Returns a human readable string representation of the disk size.

  Args:
    value: str, Disk size represented as number of bytes.

  Returns:
    A human readable string representation of the disk size.
  """
  size = float(value)
  the_unit = 'TB'
  for unit in ['bytes', 'KB', 'MB', 'GB']:
    if size < 1024.0:
      the_unit = unit
      break
    size = float(size) / 1024.0
  if size == int(size):
    return '%d %s' % (size, the_unit)
  else:
    return '%3.1f %s' % (size, the_unit)