Django model classes with the same field names and Admin

I have a model which has been working up until now. The model has 2 classes that both have some fields with the same name. I had admin customised for class1 but not 2, although class 2 was registered with the admin so I could edit it. Now I want to customise class2 in the admin but 开发者_高级运维then I start getting _ name _ errors.

I think it is caused by the field names being the same in the different classes.

How can I setup the admin so it will work with 2 nearly identical classes

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It turns out the error was being caused by:

filter_horizontal = ('screenshots')

Note the missing comma after the screenshots item:

filter_horizontal = ('screenshots',)

Thanks for having a look