'add an option to this group.
if a shortened version of a long option is specified it will
be suppressed in the help. addoption(\'--twowords\', \'--two-words\')
results in help showing \'--two-words\' only, but --twowords gets
accepted **and** the automatic destination is in args.twowords'

def addoption(self, *optnames, **attrs):

    conflict = set(optnames).intersection((name for opt in self.options for name in opt.names()))
    if conflict:
        raise ValueError(('option    names    %s    already    added' % conflict))
    option = Argument(*optnames, **attrs)
    self._addoption_instance(option, shortupper=False)
