toDotString method
Implementation
String toDotString() {
return '''
digraph "" {
graph [style=rounded fontname="Arial Black" fontsize=13 penwidth=2.6];
node [shape=rect style="filled,rounded" fontname=Arial fontsize=15 fillcolor=Lavender penwidth=1.3];
edge [penwidth=1.3];
${this.map((n) => '"$n"').join('\n')}
${this.expand((element) => this.edges(element).map((n) => '"$element" -> "$n"')).toList().join('\n')}
}''';
}