code: private String getProxyKeyUsages() {
  
      StringBuilder usage = new StringBuilder();
  
      Iterator<String> it = proxyKeyUsageList.iterator();
  
      if (it.hasNext())
        usage.append(it.next());
  
      while (it.hasNext()) {
        usage.append(", " + it.next());
      }
  
      return usage.toString();
    }
docs: /*
  Returns a formatted list of KeyUsage