NA_explicit_            NA_explicit_
NA_logical              NA_logical
all_na                  Tests for missing values
coerce_safe             coerce_safe
impute-commutative      Imputation by Cummutative Functions Impute
                        using replacement values calculated from a
                        univariate, cummuative function.
impute-constant         Impute by Constant Value Replaces 'NA's by a
                        constant
impute-noncommutative   non-commutative imputation Impute missing
                        values using non-commutative functions, i.e.
                        where the order *matters*.
n_na                    Counts how many values are NA
na.bootstrap            na.bootstrap
na.replace              Replace Missing Values
na.rm                   na.rm
na.unreplace            na.unreplace
