With a great sadness I succumb to using "".format() as the default (and only) way to do string formatting in micropython-lib. That means that my dreams of making str.format() optional in uPy won't be realized, and instead str.__modulo__ should be made such.

The reason for that is however obvious on a mid-duration thought: str.format() allows to format with several arguments without allocating intermediate tuple. So simple.

@dpgeorge , @dhylands : FYI