Three syntax warnings occur when installing python3-pivy:
/usr/lib/python3/dist-packages/pivy/quarter/QuarterWidget.py:17:
SyntaxWarning: invalid escape sequence '\C'
"""
/usr/lib/python3/dist-packages/pivy/quarter/eventhandlers/DragDropHandler.py:17:
SyntaxWarning: invalid escape sequence '\c'
"""
/usr/lib/python3/dist-packages/pivy/quarter/eventhandlers/EventHandler.py:17:
SyntaxWarning: invalid escape sequence '\c'
"""
In each case changing the offending docstring to start with 'r"""'
instead of '"""' suppresses the warnings.