I need a double inheritance for a class that is an Enum but also support my own methods. Here’s the context:
import abc from enum import Enum class MyFirstClass(abc.ABC): @abc.abstractmethod def func(self): pass class MySecondClass(Enum, MyFirstClass): VALUE_1 = 0 VALUE_2 = 1 def func(self): return 42
The declaration of
MySecondClass yields the following error:
TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases
I tried applying this stackoverflow solution by doing:
class MyMetaClass(type(Enum), type(MyFirstClass)): pass class MyFinalClass(Enum, MyFirstClass, metaclass=MyMetaClass): VALUE_1 = 0 VALUE_2 = 1 def func(self): return 42
But I get the following error:
TypeError: new enumerations should be created as `EnumName([mixin_type, ...] [data_type,] enum_type)`
Is this an issue specific to the
Enum type, or am I missing something else regarding metaclasses?
The solution to your immediate problem is:
class MyFinalClass(MyFirstClass, Enum, metaclass=MyMetaClass): pass
Enum is the last regular class listed.
For a fully functioning abstract Enum you’ll want to use the
ABCEnumMeta from this answer — otherwise missing abstract methods will not be properly flagged.