Remove SubfieldBase metaclass

common/djangoapps/util/models.py

@@ -7,6 +7,8 @@ from config_models.models import ConfigurationModel
 from django.db import models
 from django.utils.text import compress_string
 
+from openedx.core.djangoapps.util.model_utils import CreatorMixin
+
 logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
 
 
@@ -40,12 +42,10 @@ def decompress_string(value):
     return ret
 
 
-class CompressedTextField(models.TextField):
+class CompressedTextField(CreatorMixin, models.TextField):
     """ TextField that transparently compresses data when saving to the database, and decompresses the data
     when retrieving it from the database. """
 
-    __metaclass__ = models.SubfieldBase
-
     def get_prep_value(self, value):
         """ Compress the text data. """
         if value is not None: