text: from mongoengine import DynamicDocument
  from mongoengine.fields import (
      StringField, IntField, DateTimeField, BooleanField,
      FloatField, ListField, DictField
  )
  
  
  
  class AccountModel(DynamicDocument):
      username = StringField()
      blockchainn = StringField()
      referer = StringField()
      meta = StringField()
  
  
      meta = {
          'collection': 'users',
          'indexes': [
              'username',
              'referer',
              'blockchain'
          ],
  
          'auto_create_index': True,
          'index_background': True
      }
  