[Zope] testing for "REQUEST is not None"

[Magnus Heino]

>   - inside the function, REQUEST is either a Request instance (boolean
>     true) or 'None' (boolean false), so testing for
>     'if REQUEST is not None:' is equivalent to 'if REQUEST:'

Nope.

A Request instance is not the same thing as boolean True.

Instances of user-defined classes are considered False if the class defin=
es a=20
__nonzero__() or __len__() method, and that method returns the integer ze=
ro=20
or bool value False.

So using a instance as boolean true depends on the implementation of the=20
class... thats why you always need to test for None.

You can find more info about this here;=20
http://www.python.org/doc/current/lib/truth.html

--=20

  /Magnus