Invalid embedded document instance provided to an EmbeddedDocumentField

[smileisak]

Hi everyone,
I'm trying to create a code snippet to load some fixtures in mongomock via mongoengine.

products.json file:

{
  "products" :[
    {
      "ean": "328277917669",
      "name": "Product Added By Ismail",
      "family": "EMOLLIENTS & HYDRATANTS CORPS",
      "brand": "blabla",
      "assortment": "blabla",
      "area": "blaala",
      "tags": [
        {
          "name": "IDENTITE"
        }
      ]
    }]
}

Product Document and tag document:

class TagInstance(EmbeddedDocument):
    """
    This class represent an instance of the Tag used for defining product's rep's tags or conditions on questions
    values_ord is used to store values when an order is defined on values

    """
    # should be the same name of the tag
    name = StringField(required=False, max_length=200, null=True)
    # the comparator used for this tag instance
    comparator = StringField(required=False, max_length=200, null=True)
    # values of the tag inst could be one (=,<,>) or multiple values (Between, IN)
    # only one of this below fields should be used for a Tag
    values = ListField(StringField(required=False, max_length=200))
    values_ord = ListField(ListField(StringField(required=False, max_length=200), null=True))

class Product(DynamicDocument):
    """
    a class that represent a product
    """
    # Meta variables.
    meta = {'collection': 'products'}
    ean = StringField(required=False, max_length=200, null=True)
    name = StringField(required=False, max_length=200, null=True)
    family = StringField(required=False, max_length=200, null=True)
    brand = StringField(required=False, max_length=200, null=True)
    assortment = StringField(required=False, max_length=200, null=True)
    area = StringField(required=False, max_length=200, null=True)
    tags = ListField(EmbeddedDocumentField(TagInstance))

code snippet to load data to mongo passing by mongoengine:

def load_db_from_json_file(self):
        with open(self.fixtures_path + '/products.json') as data_file:
            data = json.load(data_file)
            for element in data.get('products'):
                product = Product(**element)
                product.save()

The error: