code: public static JobExecutionResult execute(Plan plan) throws Exception {
  		LocalExecutor exec = new LocalExecutor();
  		try {
  			exec.start();
  			return exec.executePlan(plan);
  		} finally {
  			exec.stop();
  		}
  	}
docs: Executes the program represented by the given Pact plan.
  
  @param pa The program's plan.
  @return The net runtime of the program, in milliseconds.
  
  @throws Exception Thrown, if either the startup of the local execution context, or the execution
  caused an exception.