help interpreting usermod man page

Hi, I put an expiration on a few id's that I want to remove now. From the man page

-e expire Specify the future date on which a login can no
longer be used; after this date, no user will be
able to access this login. This option is useful
for creating temporary logins. You may type the
value of the argument expire (which is a date) in
any format you like (except a Julian date). For
example, you may enter 10/6/90 or October 6,
1990. A value of " '' defeats the status of the
expired date.

does that mean I issue this command

usermod -e " " username

with a space in between the quotes? Or does the man page mean to leave a blank?

Aaron