code: public static String[] splitFunction(final String function) {
          if (!function.contains(".")) {
              throw new IllegalArgumentException(function);
          }
          return function.split("\\.");
      }
docs: Extract the module and function name from the function string based on '.' .
  In case of e.g. "test.ping", this method will return String array {'test','ping'}
  
  @param function string containing module and function name (e.g. "test.ping")
  @return String array containing module name as 1st element and function name as 2nd
  @throws IllegalArgumentException if a given function string does not contain a '.'