函数

可以在形参处指定默认值

def add(x = 0, y = 0):
    return x + y

检查是否作为模块运行

>>> print __name__
__main__


>>> if __name___ != '__main__':
...     print 'running as module'

一般写法

def main():
    print 'verify & debug each functions'

# call main() to call verify each functions
if __name__ == '__main__':
    main()