+                                       ->arrayNode('cache')
+                                               ->addDefaultsIfNotSet()
+                                               ->children()
+                                                       ->scalarNode('namespace')->defaultValue($defaults['cache']['namespace'])->end()
+                                                       ->integerNode('lifetime')->min(0)->defaultValue($defaults['cache']['lifetime'])->end()
+                                                       ->scalarNode('directory')->defaultValue($defaults['cache']['directory'])->end()
+                                               ->end()
+                                       ->end()
+                                       ->arrayNode('calendar')
+                                               ->addDefaultsIfNotSet()
+                                               ->children()
+                                                       ->scalarNode('calendar')->defaultValue($defaults['calendar']['calendar'])->end()
+                                                       ->scalarNode('prefix')->defaultValue($defaults['calendar']['prefix'])->end()
+                                                       ->scalarNode('project')->defaultValue($defaults['calendar']['project'])->end()
+                                                       ->scalarNode('client')->defaultValue($defaults['calendar']['client'])->end()
+                                                       ->scalarNode('secret')->defaultValue($defaults['calendar']['secret'])->end()
+                                               ->end()
+                                       ->end()