my %data = (
  multiple => 'to fail',
  #multiple => [qw{this multi-value input will fail on the constraint below}],
  single   => 'to pass',
);

my %profile = (
  required => [qw/
    multiple
    single 
    /],
  constraints => {
      multiple => [
        { name => 'constraint_1', constraint => qr/\w/ }, # pass
        { name => 'constraint_2', constraint => qr/\d/ }, # force fail 
      ],
  },
);


my $results = Data::FormValidator->check(\%data, \%profile);