afw's spatialCellExample.py relies on C++ code in the examples directory that has not been pybind11-wrapped. The code is similar to code available as part of the main library that is intended for unit testing (extra classes defined in spatialCell.cc). So one attractive fix is to modify the example to use what's there, or supplement what's there so the example can use it. (If we had time it would be especially nice to upgrade the unit test to use the additional capabilities of candidates that contain pixels, which image candidates usually do.)
Another possibility is to regenerate the wrapped code, but the code pretends to be test code and it will just bit rot again, so I hope to avoid that.