@staticmethod<EOL><INDENT>def export_diagram_plane_elements(root, diagram_attributes, plane_attributes):<DEDENT>
diagram = eTree.SubElement(root, BpmnDiagramGraphExport.bpmndi_namespace + "<STR_LIT>")<EOL>diagram.set(consts.Consts.id, diagram_attributes[consts.Consts.id])<EOL>diagram.set(consts.Consts.name, diagram_attributes[consts.Consts.name])<EOL>plane = eTree.SubElement(diagram, BpmnDiagramGraphExport.bpmndi_namespace + "<STR_LIT>")<EOL>plane.set(consts.Consts.id, plane_attributes[consts.Consts.id])<EOL>plane.set(consts.Consts.bpmn_element, plane_attributes[consts.Consts.bpmn_element])<EOL>return diagram, plane<EOL>
Creates 'diagram' and 'plane' elements for exported BPMN XML file.
Returns a tuple (diagram, plane).

:param root: object of Element class, representing a BPMN XML root element ('definitions'),
:param diagram_attributes: dictionary that holds attribute values for imported 'BPMNDiagram' element,
:param plane_attributes: dictionary that holds attribute values for imported 'BPMNPlane' element.