undefined_distribution-class: Undefined distribution class. This type of object is automatically created
in method to_explicit_distribution() when the user does not provide a concrete
distribution. This is because S4 objects do not accept NULL values.
Description
Undefined distribution class. This type of object is automatically created
in method to_explicit_distribution() when the user does not provide a concrete
distribution. This is because S4 objects do not accept NULL values.