PhpSpec\Console\Application::registerCustomMatchers PHP Method

    private function registerCustomMatchers(IndexedServiceContainer $container, array $matchersClassnames)
    {
        foreach ($matchersClassnames as $class) {
            $this->ensureIsValidMatcherClass($class);
            $container->define(sprintf('matchers.%s', $class), function () use($class) {
                return new $class();
            }, ['matchers']);
        }
    }