code: public function getFieldManager()
      {
          /* Verifica se existe Field Manager com prefixo igual a controller */
          if (! $this->fieldManager) {
              $pathClassExploded = explode('\\', get_class($this));
              $namespace = array_first($pathClassExploded);
              $resourceName = array_last($pathClassExploded);
              
              /* Verifica se existe o Field Manager para o recurso */
              if (! class_exists("{$namespace}\\FieldManagers\\{$resourceName}FieldManager")) {
                  return null;
                  echo "Crie o Field Manager {$resourceName}FieldManager em {$namespace}\\FieldManagers";
                  exit();
              }
              
              $this->fieldManager = $namespace . "\\FieldManagers\\{$resourceName}FieldManager";
          }
          
          /* Ainda precisa instanciar o objeto */
          if (is_string($this->fieldManager)) {
              return new $this->fieldManager();
          }
          
          /* Objeto já instanciado, só retornar */
          return $this->fieldManager;
      }
docs: Return instance Field Manager of controller
  
  @return object Lab123\Odin\FieldManager