public void tryCreateFacebookClient(final Collection<Client> clients) {
        val id = getProperty(FACEBOOK_ID);
        val secret = getProperty(FACEBOOK_SECRET);
        val scope = getProperty(FACEBOOK_SCOPE);
        val fields = getProperty(FACEBOOK_FIELDS);
        if (StringUtils.isNotBlank(id) && StringUtils.isNotBlank(secret)) {
            val facebookClient = new FacebookClient(id, secret);
            if (StringUtils.isNotBlank(scope)) {
                facebookClient.setScope(scope);
            }
            if (StringUtils.isNotBlank(fields)) {
                facebookClient.setFields(fields);
            }
            clients.add(facebookClient);
        }
    }
<p>tryCreateFacebookClient.</p>

@param clients a {@link java.util.List} object
pac4j-config/src/main/java/org/pac4j/config/builder/OAuthBuilder.java