How to invoke methods on the same singleton object in Python?

from __future__ import annotations
import cx_Oracle as oracle

class Connection(oracle.Connection):
        __connection = None
    
        @classmethod
        def create(cls) -> Connection:
            """Returns a singleton cx_Oracle.Connection object."""
    
            if not cls.__connection:            
                cls.__connection = oracle.connect(
                    user="xxx",
                    password="xxx",
                    dsn="xxx",
                    mode=oracle.SYSDBA
                )
    
            return cls.__connection

I want to use a singleton database connection object in my project to avoid creating a connection more than one. In this example oracle.connection method returns the instance of the parent class.(which is cx_Oracle.Connection)

My question is how can i return Connection instance (which is the class i created) instead of cx_Oracle.Connection class. Because I want to invoke some methods on my singleton object like;

connection = Connection.create()
connection.execute()

Only my Connection class will have execute method, not the parent class.