000-- the way to define a string with several lines
001--to get specific letters from a string
002-- the common error message for new beginner while running python script
http://www.cnblogs.com/smile-ls/archive/2013/05/20/3088393.html
003--
hausaufgabe--python 14- Functions for Strings
原文：http://www.cnblogs.com/Shareishappy/p/6942561.html