code: public function addOperation(Operation $operation)
      {
          $id    = $operation->getMethod().$operation->getPath();
          $group = 'Default';
  
          if ($operation->getOperation()->getOperationId()) {
              $id = $operation->getOperation()->getOperationId();
          }
  
          if ($operation->getOperation()->getTags() !== null && count($operation->getOperation()->getTags()) > 0) {
              $group = $operation->getOperation()->getTags()[0];
          }
  
          $group = trim(preg_replace('/[^a-z0-9 ]+/iu', '', $group));
          $group = Inflector::classify($group);
  
          if (!isset($this[$group])) {
              $this[$group] = [];
          }
  
          $this[$group][$id] = $operation;
  
          return $this;
      }
docs: @param Operation $operation
  
  @return self