#!/usr/bin/perl
use strict;
use warnings;
use Moo;
# Or Moose, or Mouse

use Types::Standard qw/ :all /;

has foo => (        is => 'ro', isa => Str,     required => 1 );
has bar => (        is => 'ro', isa => HashRef, required => 1 );
has flintstone => ( is => 'ro', isa => Enum[qw( Fred Wilma Pebbles BamBam )] );

# etc. . .