Syntax options:

    VARIANT | NOT VARIANT

    These clauses are synonyms for the DETERMINISTIC and NOT
    DETERMINISTIC clauses. The DETERMINISTIC clause indicates that
    the same inputs to the function will generate the same output.
    It is the same as the NOT VARIANT clause. The NOT DETERMINISTIC
    clause indicates that the output of the function does not depend
    on the inputs. It is the same as the VARIANT clause. This clause
    is deprecated. Use DETERMINISTIC instead.