+def convert(magnitude: SupportsFloat, from_thing: str, to_thing: str) -> float:
+ """Convert between units using the internal catalog.
+
+ Args:
+ magnitude: the quantity from which to convert
+ from_thing: the quantity's source unit we're coverting from
+ to_thing: the unit we are coverting to
+
+ Returns:
+ The converted magnitude. Raises on error.
+ """