## can't print the data frame because the concomitant warning changes in
## r75024 (see issue#96), and limitations of unitizer (unitizer:issue249)

$Sepal.Length
 [1] 5.1 4.9 4.7 4.6 5.0 5.4 4.6 5.0 4.4 4.9

$Sepal.Width
 [1] 3.5 3.0 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1

$Petal.Length
 [1] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5

$Petal.Width
NULL

$Species
 [1] setosa setosa setosa setosa setosa setosa setosa setosa setosa setosa
Levels: setosa versicolor virginica

nullify(structure(letters[1:2], class = "xqwer892jahaksdf"), 
    2)

Unable to convert object back to class "xqwer892jahaksdf"

Warning in nullify.default(structure(letters[1:2], class = "xqwer892jahaksdf"),  :
  Unable to convert object back to class "xqwer892jahaksdf"