toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
final seriesString = series.map((s) => s.toString()).join(', ');
return '''
{
title: ${title.toString()},
${subtitle != null ? 'subtitle: ${subtitle!.toString()},' : ''}
xAxis: ${xAxis.toString()},
yAxis: ${yAxis.toString()},
series: [ $seriesString ]
}
''';
}