assert                  Raises error if predicate is FALSE in any
                        columns selected
assert_rows             Raises error if predicate is FALSE for any row
                        after applying row reduction function
assertr                 assertr: Assertive programming for R analysis
                        pipeline.
in_set                  Returns TRUE if value in set
insist                  Raises error if dynamically created predicate
                        is FALSE in any columns selected
insist_rows             Raises error if dynamically created predicate
                        is FALSE for any row after applying row
                        reduction function
maha_dist               Computes mahalanobis distance for each row of
                        data frame
not_na                  Returns TRUE if value is not NA
num_row_NAs             Counts number of NAs in each row
verify                  Raises error if expression is FALSE anywhere
within_bounds           Creates bounds checking predicate
within_n_mads           Return a function to create robust z-score
                        checking predicate
within_n_sds            Return a function to create z-score checking
                        predicate
