installed => {
    do => sub { shift->result($self->_is_installed) },
    rules  => [
      fail    => { "Postgres not\ninstalled" => sub {! shift->result } },
      version => { "Postgres\ninstalled" => sub { shift->result } },
    ],
  },

##</code><code>##

    rules  => [
      fail    => sub { ! shift->result },
      version => sub { shift->result }
    ],