no builtin exception IOError available during module loading.

[djay]

Not sure why but if I have code like this

def resource_exists(name):
    """Return true if the given resource exists"""
    try:
        open_resource(name).close()
        return True
    except IOError:
        return False

blah = resource_exists('blah.cfg')

results in generated code like

            if (($pyjs_try_err_name == (typeof IOError == "undefined"?$m['IOError']:IOError)['__name__'])||$p['_isinstance']($pyjs_try_err,(typeof IOError == "undefined"?$m['IOError']:IOError))) {
                return false;

and if its run during a module load I get an exception like
Uncaught TypeError: Cannot read property '__name__' of undefined
because $m['IOError'] is undefined.

[djay]

Ah I think it's because IOError isn't defined at all in pyjs