'Fake the lack of the specified modules, separated with commas.'

def opt_without_module(self, option):

    self['without-module'] = option
    for module in option.split(','):
        if (module in sys.modules):
            warnings.warn(("Module    '%s'    already    imported,    disabling    anyway." % (module,)), category=RuntimeWarning)
        sys.modules[module] = None
