def mkdir(self, target_folder):
        """
        Create a folder on S3.

        Examples
        --------
            >>> s3utils.mkdir("path/to/my_folder")
            Making directory: path/to/my_folder
        """
        self.printv("Making directory: %s" % target_folder)
        self.k.key = re.sub(r"^/|/$", "", target_folder) + "/"
        self.k.set_contents_from_string('')
        self.k.close()
Create a folder on S3.

        Examples
        --------
            >>> s3utils.mkdir("path/to/my_folder")
            Making directory: path/to/my_folder