Flask Restful API nearest_node

Question

I am trying to set up an API rest in Flask using inside osmnx and a function named nearest_node but doesn't work . The code I'm using is :

import networkx as nx
import osmnx as ox
from matplotlib import pyplot as plt
from flask import Flask

app = Flask(__name__)
G = ox.load_graphml('my.graphml')
orig_node = ox.distance.nearest_nodes(G,[40.670724], [16.597054])
dest_node = ox.distance.nearest_nodes(G,[40.669731], [16.606796])
@app.route('/')

def dijkstra():
 route = nx.shortest_path(G,orig_node,dest_node,weight='length')
 route_map = ox.plot_route_folium(G, route)
 route_map.save('route.html')
 return plt.show(route_map)

if __name__ == '__main__':
 app.run(host='0.0.0.0', port=9090)

I haven't sintax error but on my homepage site I can't see nothing . There is someone that can help me ? Max