@staticmethod<EOL><INDENT>def import_parallel_gateway_to_graph(diagram_graph, process_id, process_attributes, element):<DEDENT>
BpmnDiagramGraphImport.import_gateway_to_graph(diagram_graph, process_id, process_attributes, element)<EOL>
Adds to graph the new element that represents BPMN parallel gateway.
Parallel gateway doesn't have additional attributes. Separate method is used to improve code readability.

: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 'parallelGateway'.