The abstract parent class to decorators.
Returns error. Abstract classes cannot be constructed directly.
Decorating is the process of adding methods to classes that are not part of the core
interface (Gamma et al. 1994). Use listDecorators to see which decorators are currently available. The primary
use-cases are to add numeric results when analytic ones are missing, to add complex modelling functions and
to impute missing d/p/q/r functions.
Abstract classes cannot be implemented directly. Use the decorate function to decorate distributions.
Gamma, Erich, Richard Helm, Ralph Johnson, and John Vlissides. 1994. <U+201C>Design Patterns: Elements of Reusable Object-Oriented Software.<U+201D> Addison-Wesley.