Returns value for this option from either cfg object or optparse option list, preferring the option list.

def get(self, value, cfg=None):
        """
        Returns value for this option from either cfg object or optparse option list, preferring the option list.
        """
        if value is None and cfg:
            if self.option_type == 'list':
                value = cfg.get_list(self.name, None)
            else:
                value = cfg.get(self.name, None)

        if value is None:
            value = self.default
        else:
            parse_method = getattr(self, 'parse_%s' % (self.option_type), None)
            if parse_method:
                value = parse_method(value)
        return value