[Tutor] saving output in a text file

[Danny Yoo]

>    def double(s):
>        "double: string -> string
>        doubles up the input string s."
>        return s + s


Gaah.  Typos.  My apologies.  Here's a correction to double()

    def double(s):
        """double: string -> string
        Doubles up the input string s.  For example, double("abc")
        should return "abcabc".
        """
        return s + s


> Would you be able to write a program that takes "hello world", runs it 
> through double(), and writes out "hello worldhelloworld" to disk?

I meant to say that the expected content of the file should be:

     "hello worldhello world"

My apologies; I rushed that message too quickly.