code: def NOAJS_metric(bpmn_graph):
      
  
      activities_count = all_activities_count(bpmn_graph)
      gateways_count = all_gateways_count(bpmn_graph)
  
      return activities_count + gateways_count
docs: Returns the value of the NOAJS metric (Number of Activities, joins and splits)
      for the BPMNDiagramGraph instance.
  
      :param bpmn_graph: an instance of BpmnDiagramGraph representing BPMN model.