docs: def get_file_name(query):
  	"""get_file_name(query) -> filename -- return the filename found in a
  	given, found by matching a regular expression.
  	"""
  	match = re.search(r'\S*\.[\d\w]{1,4}', query)
  	if(match):
  		filename = match.group()
  		return filename
  	else:
  		start = match.start()
  		end = match.end()
  		spaces = re.finditer(r' ', query)
  		space_index = []
  		for space in spaces:
  			space_index.append(space.start())
  		space_index.pop()
  		for i in space_index:
  			filename = query[i+1:end]
  			if(os.path.isfile(filename)):
  				return filename
  		return None