Objects from the Class
Objects can be created by calls of the form new("Gumbel", loc, scale).
  More frequently they are created via the generating function 
  Gumbel.Extends
Class "AbscontDistribution", directly.
Class "UnivariateDistribution", by class "AbscontDistribution".
Class "Distribution", by class "AbscontDistribution".concept
- Gumbel
- extreme value distribution
- absolutely continuous distribution
- S4 distribution class