@staticmethod<EOL><INDENT>def import_complex_gateway_to_graph(diagram_graph, process_id, process_attributes, element):<DEDENT>
element_id = element.getAttribute(consts.Consts.id)<EOL>BpmnDiagramGraphImport.import_gateway_to_graph(diagram_graph, process_id, process_attributes, element)<EOL>diagram_graph.node[element_id][consts.Consts.default] = element.getAttribute(consts.Consts.default)if element.hasAttribute(consts.Consts.default) else None<EOL>
Adds to graph the new element that represents BPMN complex gateway.
In addition to attributes inherited from Gateway type, complex gateway
has additional attribute default flow (default value - none).

:param diagram_graph: NetworkX graph representing a BPMN process diagram,
:param process_id: string object, representing an ID of process element,
:param process_attributes: dictionary that holds attribute values of 'process' element, which is parent of
    imported flow node,
:param element: object representing a BPMN XML 'complexGateway' element.