For matrices and data frames, function gunter()
returns an object of class gunter: a list of two elments, the
first being a matrix (‘obs’) with rows being possible
observations, and the second (‘d’) a vector with one
entry for each row of matrix obs.
For MB objects and Oarray objects, function
gunter() returns an object of class gunter_MB.
The print method returns its argument, invisibly, after printing it
coerced to a list.