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