code: public function setConfig($name, $value) {
          if (is_null($name)) {
              $this->_config = new ArrayStorage($value);
          } else {
              $this->_config->setDeepValue($name, $value);
          }
          return $this;
      }
docs: Set config value partially of completely
  @param $name
  @param $value
  @return $this