code: def warn(what, string, pos):
  
  	
  
  	pos = position(string, pos)
  
  	warnings.warn("{0} at position {1}!".format(what, pos), Warning)
docs: Combines a warning with a call to errors.position().
  
  	Simple convenience function.
  
  	Arguments:
  		string (str): The string being parsed.
  		pos (int): The index of the character that caused trouble.