docs: def sort_files_by_size(filenames, verbose = False, reverse = False):
  	"""
  	Return a list of the filenames sorted in order from smallest file
  	to largest file (or largest to smallest if reverse is set to True).
  	If a filename in the list is None (used by many pycbc_glue.ligolw based
  	codes to indicate stdin), its size is treated as 0.  The filenames
  	may be any sequence, including generator expressions.
  	"""
  	if verbose:
  		if reverse:
  			print >>sys.stderr, "sorting files from largest to smallest ..."
  		else:
  			print >>sys.stderr, "sorting files from smallest to largest ..."
  	return sorted(filenames, key = (lambda filename: os.stat(filename)[stat.ST_SIZE] if filename is not None else 0), reverse = reverse)