private static IllegalArgumentException unknownN ( int N ) {
  return new IllegalArgumentException ( "Unknown N: " + N ) ;
}

private static IllegalArgumentException unknownN ( int N ) { return new IllegalArgumentException ( " Unknown ▁ N : ▁ " + N ) ; }
(method_declaration (modifiers) type: (type_identifier) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (return_statement (object_creation_expression type: (type_identifier) arguments: (argument_list (binary_expression left: (string_literal) right: (identifier)))))))