public void execute(ProcessEngine engine, string scenarioName)
{
CaseService caseService = engine.CaseService;
CaseInstance caseInstance = caseService.createCaseInstanceByKey("case", scenarioName);
string caseInstanceId = caseInstance.Id;
CaseExecutionQuery query = caseService.createCaseExecutionQuery().caseInstanceId(caseInstanceId);
string firstHumanTaskId = query.activityId("PI_HumanTask_1").singleResult().Id;
caseService.manuallyStartCaseExecution(firstHumanTaskId);
caseService.completeCaseExecution(firstHumanTaskId);
string secondHumanTaskId = query.activityId("PI_HumanTask_2").singleResult().Id;
caseService.manuallyStartCaseExecution(secondHumanTaskId);
}