Sets the data value.
mixed|null $value: The value to set in the format as documented for the data type or NULL to unset the data value.
bool $notify: (optional) Whether to notify the parent object of the change. Defaults to TRUE. If a property is updated from a parent object, set it to FALSE to avoid being notified again.
\Drupal\Core\TypedData\ReadOnlyException If the data is read-only.
public function setValue($value, $notify = TRUE);