Save some people. Friends lack sufficient knowledge to try to solve this problem alone.
I have these 3 classes below: Historical <https://github.com/CoutinhoElias/pesquisasatisfacao/blob/master/pesquisasatisfacao/financeiro/models.py#L15-L43>, Account <https://github.com/CoutinhoElias/pesquisasatisfacao/blob/master/pesquisasatisfacao/financeiro/models.py#L46-L72>, Payment <https://github.com/CoutinhoElias/pesquisasatisfacao/blob/master/pesquisasatisfacao/financeiro/models.py#L75-L85> In the admin I can list in the History the added values of Account and Payment as well so I will search in the respective models, however I think it is interesting to also present a column with the remaining value, that is, Account - Payment (Clustered value of accounts subtracted from the payment) . I thought it would be easy to do but it returns me the following error: unsupported operand type (s) for -: 'NoneType' and 'NoneType' I know it means the message but I do not know how to solve it. Has anyone ever experienced this? Can you help me? -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/d3190fd9-0fdf-4e1d-9f3d-6a0120662b3e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
