python - How to invoke the right method in django inherited model -

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i have model classes b , c implements method f , inherits model class a. want invoke function f on instances (b , c). why do

for in a.objects.all():     a.f()

doesn't work expected?

that's because default django manager doesn't manage polymorphism. when do

for in a.objects.all():     …

all a objects of type a, , no type b or c.

you need use django-model-utils application, , it's select_subclasses tool:

for in a.objects.select_subclasses():     # type(a) returns correct subclass

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