var finish = function () {

        if (!errors.length &&
            state.parent &&
            ((options.modify && state.parent.hasOwnProperty(state.key)) || (value === undefined && self._flags.default !== undefined))) {

            state.parent[state.key] = (value !== undefined ? value : self._flags.default);
        }

        // Apply mutators as long as there are no errors

        for (var m = 0, ml = self._mutators.length; m < ml && !errors.length; ++m) {
            var err = self._mutators[m](value, state, options);
            if (err) {
                errors.push(err);
            }
        }

        // Return null or errors

        return errors.length ? errors : null;
    };