title: Query Embedded Document List in MongoEngine
body: <p>I need query a list with all embedded documents in mongoengine. Here is my schema:</p>
  
  <pre><code>class Variant(EmbeddedDocument):
      name = StringField(required=True)
      value = StringField(required=True)
  
  class Sku(Document):
      variants = ListField(EmbeddedDocumentField(Variant))
  </code></pre>
  
  <p>I can do it using mongo shell with:</p>
  
  <pre><code>db.sku.find({variants: [{'name': 'xxx', 'value': 'xxx'}]}).pretty()
  </code></pre>
  
  <p>But I haven't figure out a way to do it in mongoengine. I need the list in the document is exactly the same with the list I put in the query. Any ideas?</p>