Hi! Got this setup:
class Document(Base):
__tablename__ = 'document'
discriminator = Column('type', String(30))
__mapper_args__ = {'polymorphic_identity':'document',
'polymorphic_on': discriminator}
id = Column(Integer, primary_key=True)
I'd discourage using metaclasses as they are more difficult to use in cases
like these than mixins, which can accomplish the vast majority of use cases.
I can't help with your metaclass case since there is no code here to work with,
but in general a dynamic __mapper_args__, whether using a
