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
"""
    Variables are a generic way to store and retrieve arbitrary content or settings
    as a simple key value store within Airflow.
    """
    __tablename__ = "variable"
    __NO_DEFAULT_SENTINEL = object()
    id = Column(Integer, primary_key=True)
    key = Column(String(ID_LEN), unique=True)
    _val = Column("val", Text().with_variant(MEDIUMTEXT, "mysql"))
    description = Column(Text)
    is_encrypted = Column(Boolean, unique=False, default=False)
    def __init__(self, key=None, val=None, description=None):
        super().__init__()
        self.key = key
        self.val = val
        self.description = description
    @reconstructor
    def on_db_load(self):