"Unum is a Python module that allows defining and manipulating true quantities, i.e. numbers with units like volts, hours, meter-per-second. Consistency between units is checked at each expression evaluation; unit conversion and unit output formatting are performed automatically when needed."

I mainly work on reinsurance industry software, and we only really care about money, so I won't find much use for this. But it's worth keeping a note of - should I ever need to work with physical quantities in future, this package looks like it would be worth its weight in gold.