code: public static BpmnModel getBpmnModel(DelegateExecution execution) {
          if (execution == null) {
              throw new ActivitiException("Null execution passed");
          }
          return ProcessDefinitionUtil.getBpmnModel(execution.getProcessDefinitionId());
      }
docs: Returns the {@link BpmnModel} matching the process definition bpmn model
  for the process definition of the passed {@link DelegateExecution}.