@classmethod
def validate(cls, value: str) ->None:
    """Value validation method.

    Valid values are ``INCREASE`` and ``DECREASE``.

    Args:
      value (str): The value to validate.

    Raises:
      ValueError: Raises ValueError if an invalid value has been specified.
    """
    super().validate(value)
    if value not in ['INCREASE', 'DECREASE']:
        raise ValueError()
