Fix old cascade format function to work with Python3.
Fix old cascade format function to work with Python3.

openmv/openmv,iabdalkader/openmv,kwagyeman/openmv,openmv/openmv,kwagyeman/openmv,iabdalkader/openmv,kwagyeman/openmv,openmv/openmv,iabdalkader/openmv,iabdalkader/openmv,openmv/openmv,kwagyeman/openmv