Some example code and usage:

For linux:

(no need to install or build - just unpack)

$ cd src
$ env PYTHONPATH=. python py65/monitor.py -m 65Org16 -r ../examples/65Org16.boot.rom

Then paste in a hex file, such as ../examples/swapcase.hex

(Type in some mixed-case input and it will echo it back with the upper and lowercase swapped)