Make sure your alias for python is set to python2 if using Python 2.x or python3 if using Python 3.x.

Additionally, the provided runall_python.sh script may use a different python installation than intended. Specify a python version by navigating to the sample folder (e.g. /Samples/AddImageTest/PYTHON) and directly running the python file (e.g. python3 AddImageTest.py).

Alternatively, you can use version managers such as pyenv to force the samples to use the Python version of your choice.