Обсуждение: is this valid

If found this twice in the 7.3.2 User Manual:

ALTER TABLE products ADD COLUMN description text CHECK (description <> ”);

Shouldn't there be TWO parenthesis marks?

Dennis Gearon <gearond@fireserve.net> writes:
> If found this twice in the 7.3.2 User Manual:
> ALTER TABLE products ADD COLUMN description text CHECK (description <> ”);

Where exactly?  All I see is description <> '' ...

            regards, tom lane