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