Chart Configuration Serialization

With vaadin chart 2.1.3 I was able to serialize the chart configuration by calling
chart.getConfiguration.toString()
and than saving the json string to the database.

Now with vaadin chart 3.0.0 the toString method is no more redefined by AbstractConfigurationObject and I don't understand how to save the configuration.

I haven't tried, but there is 

static String toJSON(AbstractConfigurationObject object)

in 

com.vaadin.addon.charts.util.ChartSerialization

Thank you, that's exactly what I was looking for.