@Override
    public GraphComputer program(final VertexProgram vertexProgram) {
        this.vertexProgram = vertexProgram;
        return this;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/process/computer/AbstractHadoopGraphComputer.java