sub validate {
    my $input = shift;
    my %arg = @_;

    for (@{$arg{as}}) {
        my $func = "validate_$_";
        my $package = __PACKAGE__ . '::';
        no strict 'refs';

        if (exists ${ $package }{$func}) {
            $func = *{ ${ $package }{$func} }{CODE};
            return unless $func->($input);


        } else {
            # throw exception and/or return
        }
    }

    warn "validated $input";
    return 1;
}