/// <summary>New blank labeled node subject.</summary>
 public static SubjectBuilder ForBlank(this GraphBuilder self, ReadOnlySpan <char> label, out BlankNode node)
 {
     node = self.Rdf().Blank(self.GraphId(), label);
     return(self.For(node));
 }
 /// <summary>New blank labeled node subject.</summary>
 public static SubjectBuilder ForBlank(this GraphBuilder self, string label, out BlankNode node)
 {
     node = self.Rdf().Blank(self.GraphId(), label);
     return(self.For(node));
 }