Used python_2_unicode_compatible from six.

django.utils.encoding.python_2_unicode_compatible() alias was removed
in Django 3.0.

@@ -7,8 +7,8 @@ from django.contrib.sites.models import Site
 from django.db import models
 from django.db import models
 from django.urls import reverse
 from django.urls import reverse
 from django.utils import timezone
 from django.utils import timezone
-from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 from django.utils.translation import ugettext_lazy as _
+from six import python_2_unicode_compatible
 
 
 from .managers import CommentManager
 from .managers import CommentManager
 
 

 from django.conf import settings
 from django.conf import settings
 from django.db import models
 from django.db import models
 from django.utils import timezone
 from django.utils import timezone
-from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 from django.utils.translation import ugettext_lazy as _
+from six import python_2_unicode_compatible
 
 
 from .abstracts import (
 from .abstracts import (
     COMMENT_MAX_LENGTH, BaseCommentAbstractModel, CommentAbstractModel,
     COMMENT_MAX_LENGTH, BaseCommentAbstractModel, CommentAbstractModel,

@@ -42,5 +42,5 @@ setup(
     packages=find_packages(exclude=['tests', 'tests.*']),
     packages=find_packages(exclude=['tests', 'tests.*']),
     include_package_data=True,
     include_package_data=True,
     test_suite='tests.runtests.main',
     test_suite='tests.runtests.main',
-    install_requires=['Django>=1.11']
+    install_requires=['Django>=1.11', 'six']
 )
 )

@@ -6,7 +6,7 @@ more information.
 from __future__ import unicode_literals
 from __future__ import unicode_literals
 
 
 from django.db import models
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
+from six import python_2_unicode_compatible
 
 
 
 
 @python_2_unicode_compatible
 @python_2_unicode_compatible