Used by Variable/Connection.

https://github.com/apache/airflow/blob/894741e311ffd642e036b80d3b1b5d53c3747cad/airflow/secrets/metastore.py#L32

"""
        Verify that ``extra`` is a JSON-encoded Python dict.
        From Airflow 3.0, we should no longer suppress these errors but raise instead.
        """
        if extra is None:
            return None
        try:
            extra_parsed = json.loads(extra)
            if not isinstance(extra_parsed, dict):
                warnings.warn(
                    "Encountered JSON value in `extra` which does not parse as a dictionary in "
                    f"connection {conn_id!r}. From Airflow 3.0, the `extra` field must contain a JSON "
                    "representation of a Python dict.",
                    RemovedInAirflow3Warning,
                    stacklevel=3,
                )
        except json.JSONDecodeError:
            warnings.warn(
                f"Encountered non-JSON in `extra` field for connection {conn_id!r}. Support for "
                "non-JSON `extra` will be removed in Airflow 3.0",
                RemovedInAirflow3Warning,
                stacklevel=2,
            )
        return None
    @reconstructor
    def on_db_load(self):