Tag "multipleinheritance"

Multiple inheritance of newforms and modelforms

If you try to use multiple inheritance with a modelform (to mix in some fields from an already existing form class for example) you'll get the following rather terrifying error: > "Error when calling the metaclass bases metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases" The solution is to first create the ModelForm, then create a NEW class that inherits from both the ModelForm and the form you want to mixin, then finally apply the recipe from here: [http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197](http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197)