'Adds a new name or names to a policy
:param policy_index: index of a policy in this policy collection.
:param aliases: arbitrary number of string policy names to add.'

def add_policy_alias(self, policy_index, *aliases):

    policy = self.get_by_index(policy_index)
    for alias in aliases:
        if (alias.upper() in self.by_name):
            raise PolicyError(('Duplicate    name    %s    in    use    by    policy    %s' % (alias, self.get_by_name(alias))))
        else:
            policy.add_name(alias)
            self.by_name[alias.upper()] = policy
