anchor.diff:      .targetEntityId(<ITEM_ID>);
   client.createEvent(viewEvent);
   
  +// A user buys an item
  +Event viewEvent = new Event()
  +    .event("buy")
  +    .entityType("user")
  +    .entityId(<USER_ID>)
  +    .targetEntityType("item")
  +    .targetEntityId(<ITEM_ID>);
  +client.createEvent(viewEvent);
  +
   ```
     </div>
     <div data-tab="REST API" data-lang="json">
  
positive.code: 
  ## Using the Engine
  
  Now, You can retrieve predicted results. To retrieve 4 items which are similar to item ID "i1". You send this JSON `{ "items": ["i1"], "num": 4 }` to the deployed engine and it will return a JSON of the recommended items. Simply send a query by making a HTTP request or through the `EngineClient` of an SDK:
  
  <div class="tabs">
    <div data-tab="Python SDK" data-lang="python">
  
negative.code: 
  This engine template provides personalized recommendation for e-commerce alike applications.
  
  The template has the following features:
  
  - handle out of stock items with the itemConstraint event
  - recommend items to new user who signs up after the model is trained.
  - recommend unseen items only.
  
  WARNING: This template requires PredictionIO version >= 0.8.7
  
  
  ## Usage
  
  