FourSquare API - результаты не возвращены

Question

Я использую приведенный ниже код для перебора серии почтовых индексов Лондона, и он возвращает ошибку, которую я не смог исправить. Любые идеи - я думаю, что возвращаемые данные не включают имя, но не уверены.

Код

 def getNearbyVenues(names, latitudes, longitudes, radius=1000):

    venues_list=[]
    for name, lat, lng in zip(names, latitudes, longitudes):
        print(name)

        # create the API request URL
        url = 'https://api.foursquare.com/v2/venues/explore?&client_id={}&client_secret={}&v={}&ll={},{}&radius={}&limit={}'.format(
            CLIENT_ID, 
            CLIENT_SECRET, 
            VERSION, 
            lat, 
            lng, 
            radius, 
            LIMIT)

        # make the GET request
        results = requests.get(url).json()['response'].get('groups',[{}])[0].get('items')
        # return only relevant information for each nearby venue
        venues_list.append([(
            name, 
            lat, 
            lng, 
            v['venue']['name'], 
            v['venue']['location']['lat'], 
            v['venue']['location']['lng'],  
            v['venue']['categories'][0]['name']) for v in results])

    nearby_venues = pd.DataFrame([item for venue_list in venues_list for item in venue_list])
    nearby_venues.columns = ['Name', 
                  'latitude', 
                  'longitude', 
                  'Venue', 
                  'Venue Latitude', 
                  'Venue Longitude', 
                  'Venue Category']

    return(nearby_venues)

Ошибка

TypeError                                 Traceback (most recent call last)
<ipython-input-54-110fa1855079> in <module>
      1 london_venues = getNearbyVenues(names=df2['Postcode'],
      2                                    latitudes=df2['Latitude'],
----> 3                                    longitudes=df2['Longitude']
      4                                   )

<ipython-input-52-0754ad0a5b0e> in getNearbyVenues(names, latitudes, longitudes, radius)
     25             v['venue']['location']['lat'],
     26             v['venue']['location']['lng'],
---> 27             v['venue']['categories'][0]['name']) for v in results])
     28 
     29     nearby_venues = pd.DataFrame([item for venue_list in venues_list for item in venue_list])

TypeError: 'NoneType' object is not iterable