title: How do I access an object value in a map fetched and extracted from firebase realtime database
body: <p>I am beginner self-learner in dart so forgive me a trivial question for most pros (that's my first one ever though).
  So here it goes:</p>
  <p>I am fetching data from Firebase with this code:</p>
  <pre><code>Future&lt;void&gt; fetchAndSetData() async {
      final url =
          'my end point URL';
      final response = await http.get(url);
      final extractedData = json.decode(response.body) as Map&lt;String, dynamic&gt;;
      if (extractedData == null) {
        return;
      }
  final List&lt;CarData&gt; loadedCars = [];
  extractedData.forEach((carId, carDetails) {
    loadedCars.add(
        CarData(
      id: carDetails['id'],
      title: carDetails['year'],
      emotion: carDetails['brand'],
      timeStamp: carDetails['timeStamp'],
    ));
  </code></pre>
  <p>Now, I get an example map  (just one entry in Firebase for now):</p>
  <pre><code>print(extractedData);
  </code></pre>
  <p>result:</p>
  <pre><code>{-MTGYiJ-P8fN0qhQ3_zC: {brand: Ferrari, id: -MS8qMI3FtVxMBg3P9hm, timeStamp: 2021-02-11T15:46:38.550621, year: 2019}}
  </code></pre>
  <p>CartData values are stored properly and I managed to display them in a GridView. Although, I need to count all Ferraris in the database but I cannot access the object values inside the map.</p>
  <p>when I:</p>
  <pre><code> print(extractedData.keys);
   print(extractedData.values);
  </code></pre>
  <p>I get proper response (I guess):</p>
  <pre><code>I/flutter (18184): (-MTGYiJ-P8fN0qhQ3_zC)
  I/flutter (18184): ({brand: Ferrari, id: -MS8qMI3FtVxMBg3P9hm, timeStamp: 2021-02-11T15:46:38.550621, year: 2019})
  </code></pre>
  <p>But when I:</p>
  <pre><code>print(extractedData.containsValue('Ferrari'));
  </code></pre>
  <p>I get response: 'false' and without this I cannot do anything with further counting logic.</p>
  <p>Could someone please enlight me what am I doing wrong? Many thanks in advance! </p>