def add_outgoing_flow(node_id, successor_node_id, bpmn_diagram):
if bpmn_diagram.diagram_graph.node[node_id].get(consts.Consts.outgoing_flow) is None:<EOL><INDENT>bpmn_diagram.diagram_graph.node[node_id][consts.Consts.outgoing_flow] = []<EOL><DEDENT>bpmn_diagram.diagram_graph.node[node_id][consts.Consts.outgoing_flow].append(get_flow_id(node_id, successor_node_id))<EOL>
:param node_id:
:param successor_node_id:
:param bpmn_diagram: