code: protected function _setData($key, $value)
      {
          $store = $this->_getDataStore();
          try {
              $this->_containerSet($store, $key, $value);
          } catch (InvalidArgumentException $e) {
              throw $this->_createOutOfRangeException($this->__('Invalid store'), null, $e, $store);
          } catch (OutOfRangeException $e) {
              throw $this->_createInvalidArgumentException($this->__('Invalid key'), null, $e, $store);
          }
      }
docs: Assign a single piece of data.
  
  @since [*next-version*]
  
  @param string|int|float|bool|Stringable $key   The key, for which to assign the data.
  Unless an integer is given, this will be normalized to string.
  @param mixed                            $value The value to assign.
  
  @throws InvalidArgumentException    If key is invalid.
  @throws OutOfRangeException         If internal data store is invalid.
  @throws ContainerExceptionInterface If error occurs while writing to container.