protected String formatEmailBody(final String contents) {
        val sub = new StringSubstitutor(this.parameters, "${", "}");
        return sub.replace(contents);
    }
Add parameter.

@param key    the key
@param object the object
@return the email message body builder
core/cas-server-core-notifications-api/src/main/java/org/apereo/cas/notifications/mail/EmailMessageBodyBuilder.java