public T vertexProcessor(final BiConsumer<Vertex,Map<String,Object>> vertexProcessor){
  this.vertexProcessor=Optional.ofNullable(vertexProcessor);
  return extendingClass.cast(this);
}

public T vertexProcessor ( final BiConsumer < Vertex , Map < String , Object > > vertexProcessor ) { this . vertexProcessor = Optional . ofNullable ( vertexProcessor ) ; return extendingClass . cast ( this ) ; }
the function supplied here may be called more than once per vertex depending on the implementation .
