+ """Constructs a new :class:`Rate` from a multiplier, percentage, or
+ percent change. One and only one of these may be passed. These are
+ a little confusing so here's an example...
+
+ .. note::
+
+ A multiplier of 1.5x is the same as a percentage of 150% and
+ is also the same as a 50% change. Let's examine an original
+ amount of 100. Multiplying it by a 1.5x multiplier yields 150.
+ Multiplying it by 150% yields 150. Increasing it by 50% also
+ yields 150.
+
+ Args:
+ multiplier: provides the number that you would multiply a base
+ amount by to modify it
+ percentage: provides the multiplier as a percentage
+ percent_change: provides the multiplier as a percent change to
+ the base amount
+ """