Link: https://github.com/apache/airflow/blob/main/airflow/models/variable.py

Methods to migrate:

- val
- set 
- delete
- update

Note that get_variable_from_secrets shouls still be executed locally.

It may be better to first close https://github.com/apache/airflow/issues/28267
"""
        Logs a warning if a variable exists outside of the metastore.
        If we try to write a variable to the metastore while the same key
        exists in an environment variable or custom secrets backend, then
        subsequent reads will not read the set value.
        :param key: Variable Key
        """
        for secrets_backend in ensure_secrets_loaded():
            if not isinstance(secrets_backend, MetastoreBackend):
                try:
                    var_val = secrets_backend.get_variable(key=key)
                    if var_val is not None:
                        log.warning(
                            "The variable {key} is defined in the {cls} secrets backend, which takes "
                            "precedence over reading from the database. The value in the database will be "
                            "updated, but to read it you have to delete the conflicting variable "
                            "from {cls}".format(key=key, cls=secrets_backend.__class__.__name__)
                        )
                        return
                except Exception:
                    log.exception(
                        "Unable to retrieve variable from secrets backend (%s). "
                        "Checking subsequent secrets backend.",
                        type(secrets_backend).__name__,
                    )
            return None
    @staticmethod
    def get_variable_from_secrets(key: str) -> str | None: