use Moose;
has 'param' => (is=>'ro', required=>1);
has 'parsing_error' => (is=>'ro', required=>1);
sub status_code { 400 }
sub error { "JSON decode error for parameter '@{[ $_[0]->param]}': @{[ $_[0]->parsing_error]}" }
__PACKAGE__->meta->make_immutable;