def _actor_property(self, event, cameo_code, actor_regex):
        """
        Determine the property to use for modeling an actor
        Args:
            event: one of "event1", "event2" or "event3"
            cameo_code: one of the cameo codes
            actor_regex: one of the regexes above

        Returns:

        """
        if cameo_code not in self.mapping:
            return None

        arguments = self.mapping[cameo_code][event + "-arguments"]
        if not isinstance(arguments, list):
            arguments = [arguments]

        result = list()
        for a in arguments:
            match = re.search(actor_regex, a)
            if match:
                result.append(match.group(1))
        return result[0] if len(result) > 0 else None