[web server] #1642893 issue a 403 instead of a 500 on Unauthorized exception To do so, we allow an arbitrary code to be passed to ``error_handler``. Default error code is still 500.

from os.path import join
assert __file__.endswith(join('scripts', 'script1.py')), __file__
assert '__main__' == __name__, __name__
assert [] == __args__, __args__