David Binger wrote:
> I like to know that attribute assignment will not raise an exception,

Why?  There's a philosophy in C/Java that certain operations should not
cause exceptions, which is why the operators (==, +, [], etc) are
restricted to primitive types.  But that leads to ghastly constructs like:

    string1.lessThan(string2)            # string1 < string2
    substr(s, 1, 3)                      # s[1:4]
    vector_.set(1, 2.0)                  # float_[1] = 2.0

These enforce an arbitrary rule ("operators should not raise exceptions")
at the expense of readability.  I just assume that exceptions may occur at
any point in a program.  What's the harm in having to remember that
'session.user = me' might raise an exception?