I'm trying to write a driver that works with both Python 2 and Python 3. It works and passes all tests, but it cannot create a memory savable memory map when it downloads from the radio.

I can choose MemoryMapBytes, which works in Py3, or  MemoryMap, which is implemented in both but which results in a mmap that cannot be written to a file.  I'm now officially lost, which is my usual state. Any suggestions?