walk: walk the filesystem (just like os.walk).
        Use like:

        path = URI('/some/dir')
        for root, dirs, files in path.walk():
            do_something()

        root will be an URI object.

def walk(self, topdown=True, followlinks=True):
        """
        walk: walk the filesystem (just like os.walk).
        Use like:

        path = URI('/some/dir')
        for root, dirs, files in path.walk():
            do_something()

        root will be an URI object.
        """
        return self.connection.walk(self, topdown=topdown, followlinks=followlinks)