How to set up a custom type in Sqlalchemy

I am currently trying to get data from a given database using Sqlalchemy. This has worked great for me so far. However, now I have to read this table

create table DISPLAYOPTIONS (
  DOID integer constraint DO_PK primary key 
        USING INDEX (create index DO_PK_IX on DISPLAYOPTIONS(DOID) ),
  OPT dispopt
);

      

        
        
        
      

    

where dispopt

is a custom type defined as

CREATE OR REPLACE TYPE DISPOPT AS OBJECT (
  LABEL_X varchar2(50),
  LABEL_Y varchar2(50),
  LABEL_Z varchar2(50)
);

      

        
        
        
      

    

How do you define custom types in Sqlalchemy? I found in the documentation http://docs.sqlalchemy.org/en/rel_0_9/core/types.html#creating-new-types Is this the correct starting point? Do you know a few examples that are close to the problem I am facing?

Thank you very much and best wishes,

What I have tried now: I found this on Stackoverflow: How do I create composite columns with a SQLAlchemy declaration? link to documentation: http://docs.sqlalchemy.org/en/latest/orm/mapper_config.html#composite-column-types

and configure:

class DISPOPT(object):
    def __init__(self, LABEL_X, LABEL_Y, LABEL_Z):
        self.LABEL_X = LABEL_X
        self.LABEL_Y = LABEL_Y
        self.LABEL_Z = LABEL_Z 

    def __composite_values__(self):
        return self.LABEL_X, self.LABEL_Y, self.LABEL_Z

class DISPLAYOPTIONS(Base):
    __tablename__ = "DISPLAYOPTIONS"

    DOID = Column(Integer, primary_key = True)

    OPT = composite(
        DISPOPT,
        Column('LABEL_X', String(50)),
    Column('LABEL_Y', String(50)),
    Column('LABEL_Z', String(50)) 
)

      

        
        
        
      

    

But still I am getting error messages from the database.