I'm sure you've already considered this, but maybe use a checkbox instead,
as it's specifically designed to handle true/false. The SELECT widget and
associated IS_IN_SET is designed to return a string value. So If you really
want to use a select box for this instead of a checkbox, then you need to do
the boolean parsing yourself. Also, depending on the database you are
using, you may be able to substitute 'True' and 'False' with 1 and 0, which
the database may automatically parse to a boolean on insert/update.
