Database connection hasn't close

[Blenzz]

    def connect_to_postgres(
        self,
        host: str = None,
        dbname: str = None,
        user: str = None,
        password: str = None,
        port: int = None,
    ):
        """
        Connect to postgres using the psycopg2 connector. This is just a helper function to set [`vn.run_sql`][vanna.base.base.VannaBase.run_sql]
        **Example:**
        ```python
        vn.connect_to_postgres(
            host="myhost",
            dbname="mydatabase",
            user="myuser",
            password="mypassword",
            port=5432
        )
        ```
        Args:
            host (str): The postgres host.
            dbname (str): The postgres database name.
            user (str): The postgres user.
            password (str): The postgres password.
            port (int): The postgres Port.
        """

        try:
            import psycopg2
            import psycopg2.extras
        except ImportError:
            raise DependencyError(
                "You need to install required dependencies to execute this method,"
                " run command: \npip install vanna[postgres]"
            )

        if not host:
            host = os.getenv("HOST")

        if not host:
            raise ImproperlyConfigured("Please set your postgres host")

        if not dbname:
            dbname = os.getenv("DATABASE")

        if not dbname:
            raise ImproperlyConfigured("Please set your postgres database")

        if not user:
            user = os.getenv("PG_USER")

        if not user:
            raise ImproperlyConfigured("Please set your postgres user")

        if not password:
            password = os.getenv("PASSWORD")

        if not password:
            raise ImproperlyConfigured("Please set your postgres password")

        if not port:
            port = os.getenv("PORT")

        if not port:
            raise ImproperlyConfigured("Please set your postgres port")

        conn = None

        try:
            conn = psycopg2.connect(
                host=host,
                dbname=dbname,
                user=user,
                password=password,
                port=port,
            )
        except psycopg2.Error as e:
            raise ValidationError(e)

        def run_sql_postgres(sql: str) -> Union[pd.DataFrame, None]:
            if conn:
                try:
                    cs = conn.cursor()
                    cs.execute(sql)
                    results = cs.fetchall()

                    # Create a pandas dataframe from the results
                    df = pd.DataFrame(
                        results, columns=[desc[0] for desc in cs.description]
                    )
                    return df

                except psycopg2.Error as e:
                    conn.rollback()
                    raise ValidationError(e)

                except Exception as e:
                    conn.rollback()
                    raise e

        self.dialect = "PostgreSQL"
        self.run_sql_is_set = True
        self.run_sql = run_sql_postgres

Database connection hasn't close

[Blenzz]

i can't get the connection object to operate it