code: private function generateConfigCreatorMethod(ConfigService $config)
      {
          $configClass = Util::normalizeFqcn($config->getClass());
          $configData  = var_export($config->getData(), true);
  
          return <<<PHP
  
      public function getAppConfig() : {$configClass} 
      {
          if (isset(\$this->singletons['{$config->getId()}}'])) {
              return \$this->singletons['{$config->getId()}'];
          }
          
          \$data = {$configData}; 
          
          return \$this->singletons['{$config->getId()}'] = new {$configClass}(\$data);  
      }
  
  PHP;
      }
docs: Generates the creator method for the config
  
  @param ConfigService $config
  
  @return string