protected function getObjectManager( $object )
    {
        $namespace = '\\EzSystems\\BehatBundle\\ObjectManager\\';
        if ( empty( $this->objectManagers[$object] ) )
        {
            $class = $namespace . $object;

            if (
                ! class_exists( $class )
                && is_subclass_of( $class, $namespace . 'ObjectManagerInterface' )
            )
            {
                throw new \Exception( "Class '{$object}' not found or it doesn't implement '{$namespace}ObjectManagerInterface'" );
            }

            $this->objectManagers[$object] = $class::instance( $this );
        }

        return $this->objectManagers[$object];
    }