our $profile = {
  filters  => ['trim'],
  required => [ 
    'Field1',
    'Field2',
  ],
  constraint_methods => {
    'Field1' => [
      {
        name              => 'not_positive',
        constraint_method => sub {
            my ($dfv, $val) = @_;
            return $val =~ /\A\d+\z/,
        }
      },
    ],
    'Field2' => [
      {
        name              => 'not_positive',
        constraint_method => sub {
          my ($dfv, $val) = @_;
            return $val =~ /\A\d+\z/,
        },
      },
      {
        name              => 'field2_too_big',
        params            => [ qw(Field1 Field2) ],
        constraint_method => sub {
          my ($dfv, $f1, $f2) = @_;
          no warnings qw(uninitialized);
          return $f2 < $f1;
        },
      },
    ],
  },
  msgs => {
    invalid_seperator => ' ## ',
    format            => 'ERROR: %s', 
    missing           => 'FIELD IS REQUIRED',
    invalid           => 'FIELD IS INVALID',
    prefix            => 'err_',
    constraints       => {
      not_positive   => 'MUST BE POSITIVE',
      field2_too_big => 'MUST BE < Field1',
    }
  },
};