flask cors policy no ‘access-control-allow-origin’

# initialization
app = Flask(__name__)
app.config['SECRET_KEY'] = 'the quick brown fox jumps over the lazy   dog'
app.config['CORS_HEADERS'] = 'Content-Type'

cors = CORS(app, resources={r"/foo": {"origins": "http://localhost:port"}})

@app.route('/foo', methods=['POST'])
@cross_origin(origin='localhost',headers=['Content- Type','Authorization'])
def foo():
    return request.json['inputVar']

if __name__ == '__main__':
   app.run()

Here is what the above code is Doing:
1. We are importing the Flask class from the flask module.
2. We are creating an instance of the Flask class.
3. We are then using the route() decorator to tell Flask what URL should trigger our function.
4. The function is given a name which is also used to generate URLs for that particular function, and returns the message we want to display in the user’s browser.