public static Set<String> authorityListToSet(
			Collection<? extends GrantedAuthority> userAuthorities) {
		Assert.notNull(userAuthorities, "userAuthorities cannot be null");
		Set<String> set = new HashSet<>(userAuthorities.size());

		for (GrantedAuthority authority : userAuthorities) {
			set.add(authority.getAuthority());
		}

		return set;
	}