code: public boolean isLambdaArgument(String name) {
          for (Map<String,Object> arguments : lambdaArguments) {
              if (arguments.containsKey(name)) {
                  return true;
              }
          }
          return false;
      }
docs: Determine if the specified name is recognised as the name of a lambda
  argument.
  
  @param name The name of the lambda argument
  
  @return <code>true</code> if the name is recognised as the name of a
  lambda argument, otherwise <code>false</code>
  
  @since EL 3.0