sub move_to_group {
my( $self, $to_group, $to_position ) = @_;
- $self->throw_exception ('move_to_group() expects a group specification')
- unless defined $to_group;
-
- # if we're given a string, turn it into a hashref
+ # if we're given a single value, turn it into a hashref
unless (ref $to_group eq 'HASH') {
my @gcols = $self->_grouping_columns;