基础学习:function

1.function
   1.key word:def x(arguments)
   2.docstring,at the firstline of function body,for example'***print hello world***'
   3.arguments style:formal and positonal.
	definition like:
		1.(a,keyword1="a",keyword1="b")
		2.(a,*arguments1,**keywordTypeArguments2)
        invoke like:
		1.(1,keyword1="x") 
		2.(a,x,d,c,...,keyword1="x1",keywod2="x2"...)
		3.(*args)  (**args)

    [color=red]4.hard to know:
	4.7.5 Lambda Forms[/color]