这是枚举：

CREATE TYPE public.enum_log_priority AS ENUM (
    'critical','error','warning','notice','debug'
);

这是功能：

CREATE OR REPLACE FUNCTION public.log_write(
    _message text,_priority text
) RETURNS integer AS
$body$
BEGIN
    _priority = lower(_priority);
    INSERT INTO log (message,priority) VALUES (_message,_priority);

    RETURN 0;
END
$body$
LANGUAGE 'plpgsql';

我知道这不行：

ERROR: column “priority” is of type enum_log_priority but expression is of type text

但我该怎么办？