Why is giving me an error?

import 'dart:convert';
import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:intl/intl.dart';
import 'package:timeago/timeago.dart' as timeago;
import '../../flutter_flow/lat_lng.dart';
import '../../flutter_flow/place.dart';
import '../../flutter_flow/uploaded_file.dart';
import '../../flutter_flow/custom_functions.dart';

Color? tabColor(int? selectedIndex) {
  /// MODIFY CODE ONLY BELOW THIS LINE

  List<Color> tabColor = [
    Color(0xFF272D2B), // tab 1 color
    Color(0xFF50723C), // tab 2 color
    Color(0xFF3066BE), // tab 3 color
    Color(0xFFFF5A5F), // tab 4 color
    Color(0xFFFCAB10), // tab 5 color
  ];
  return selectedIndex != null ? tabColors[selectedIndex] : null;

  /// MODIFY CODE ONLY ABOVE THIS LINE
}