title: The argument type 'ProductModel?' can't be assigned to the parameter type 'ProductModel'
body: <p>I'm making a midel to upload product image,price and name to firebase then i face this error (The argument type 'ProductModel?' can't be assigned to the parameter type 'ProductModel'.)</p>
  <pre><code>    class ProductProvider with ChangeNotifier {
    List&lt;ProductModel&gt; pizzaProductList = [];
    ProductModel? productModel;
  
    fatchPizzaproductData() async {
     // List&lt;ProductModel&gt; newList = [];
  
      QuerySnapshot value =
          await FirebaseFirestore.instance.collection(&quot;PizzaProducts&quot;).get();
  
       pizzaProductList = value.docs.map((element) {
        return ProductModel(
          productImage: element.get(&quot;productImage&quot;),
          productName: element.get(&quot;productName&quot;),
          productPrice: element.get(&quot;productPrice&quot;),
        );
      }).toList();
      
    }
  
    get getPizzaproductDataList {
      return pizzaProductList;
    }
  }
  </code></pre>