code: public function addDocument($type, $number)
      {
          if ($this->documents === null) {
              $this->documents = [];
          }
  
          $document = new stdClass();
          $document->type = $type;
          $document->number = $number;
  
          $this->documents[] = $document;
  
          return $this;
      }
docs: @param string $type
  @param string $number
  
  @return Consumer