Whit scrapy, I receive this `NoneType` error when I launch my spider: 

> 
> if 'Jockey' in tab\_arrivee\_th: TypeError: argument of type 'NoneType'
>  is not iterable
> 
> 
> 

The code works fine in the console test with a `list`, but not with the `response.css`. 
I think the problem comes from the `response_arrivee_th`, and I don't understand why, because the 'scrapy shell' gives me a list in return, and it's the same that I use in the test.

```
def parse(self, response):

    tab_arrivee_th = response.css('.arrivees th::text').extract()

  # list obtained whit the response.css from above in scrapy shell

  # tab_arrivee_th = ['Cl.', 'N°', 'Cheval', 'S/A', 'Œill.', 'Poids', 'Corde', 'Ecart', 'Jockey', 'Entraîneur', 'Tx', 'Récl.', 'Rapp. Ouv.']

    if 'Jockey' in tab_arrivee_th:
        col_jockey = tab_arrivee_th.index('Jockey') + 1
    elif 'Driver' in tab_arrivee_th:
        col_jockey = tab_arrivee_th.index('Driver') + 1
    else:
        col_jockey = 0

    jockey = partant.css('td:nth-child(' + str(col_jockey) + ') > a::text').extract()

```

> 
> if 'Jockey' in tab\_arrivee\_th: TypeError: argument of type 'NoneType'
>  is not iterable
> 
> 
> 

thx for the help