code: public String keyDefault(String keyName, String defaultValue) {
  
          return getMessages().keyDefault(keyName, defaultValue);
      }
docs: Returns the localized resource string for the given message key,
  checking the workplace default resources and all module bundles.<p>
  
  If the key was not found, the provided default value
  is returned.<p>
  
  @param keyName the key for the desired string
  @param defaultValue the default value in case the key does not exist in the bundle
  @return the resource string for the given key it it exists, or the given default if not
  
  @see CmsMessages#keyDefault(String, String)