code: def get_all_gateways(bpmn_graph):
      
      gateways = filter(lambda node: node[1]['type'] in GATEWAY_TYPES, bpmn_graph.get_nodes())
  
      return gateways
docs: Returns a list with all gateways in diagram
  
      :param bpmn_graph: an instance of BpmnDiagramGraph representing BPMN model.
      :return: a list with all gateways in diagram