Added missing "the" word

docs/tutorial/1-serialization.md

@@ -143,7 +143,7 @@ The first thing we need to get started on our Web API is to provide a way of ser
             # Create new instance
             return Snippet(**attrs)
 
-The first part of serializer class defines the fields that get serialized/deserialized.  The `restore_object` method defines how fully fledged instances get created when deserializing data.
+The first part of the serializer class defines the fields that get serialized/deserialized.  The `restore_object` method defines how fully fledged instances get created when deserializing data.
 
 Notice that we can also use various attributes that would typically be used on form fields, such as `widget=widgets.Textarea`.  These can be used to control how the serializer should render when displayed as an HTML form.  This is particularly useful for controlling how the browsable API should be displayed, as we'll see later in the tutorial.