I'm disinclined to make a new method and instead prefer to go the route of having a formatting option.  For the most part, we want the methods to be limited to those in the spec (the API is already huge).  The other reason is that output formatting options are what __format__() method was intended to address.

If you want to go further, it would be reasonable to bring https://bugs.python.org/issue8060 back to life.  The final entry in that tracker item recommended moving the discussion to python ideas or into a PEP (like was done for the thousands separator format option).  There are many viewpoints to consider before jumping to codify one particular approach into the standard library.