Problems displaying two fields in same line in django admin

I 开发者_运维问答am having this weird problem of displaying two fields in the same line. According to django docs, for that I just need to wrap the two fields in a tuple. For eg, lets say I have two fields A and B, so what I can do is

fields= (('A','B'),'C'.....)

However it is showing the following error,

MyModel.fields refers to field '('A', 'B')' that is missing from the form. Is it because of the version of django? This is really weird