code: public static SelectedRule rule(String rule, ArgumentBuilder arguments) throws Exception
      {
          if (AunitRuntime.getParserFactory() == null) throw new IllegalStateException("Parser factory not set by configuration");
  
          for (Method method : collectMethods(AunitRuntime.getParserFactory().getParserClass()))
          {
              if (method.getName().equals(rule))
              {
                  return new SelectedRule(method, arguments.get());
              }
          }
  
          throw new Exception("Rule " + rule + " not found");
      }
docs: Select a rule to be used as a starting point in
  
  @param rule      the name of the rule to select
  @param arguments arguments to be passed in the invocation of the rule when parsing
  @return the selected rule
  @throws Exception if no rule can be found
  @see #parse(String, SelectedRule)
  @see #args(Object...)