diff --git a/djangocms_bootstrap4/contrib/bootstrap4_grid/models.py b/djangocms_bootstrap4/contrib/bootstrap4_grid/models.py
index 0d11993..98bcd0d 100644
--- a/djangocms_bootstrap4/contrib/bootstrap4_grid/models.py
+++ b/djangocms_bootstrap4/contrib/bootstrap4_grid/models.py
@@ -2,17 +2,26 @@
 
 from django.db import models
 from django.utils.translation import gettext_lazy as _
-from django.utils.translation import ungettext
+
+from django.utils.translation import ngettext
 
 from cms.models import CMSPlugin
 
 from djangocms_bootstrap4.constants import DEVICE_SIZES
 from djangocms_bootstrap4.fields import AttributesField, IntegerRangeField, TagTypeField
-from djangocms_bootstrap4.helpers import get_choices_match, get_first_choice, mark_safe_lazy
+from djangocms_bootstrap4.helpers import (
+    get_choices_match,
+    get_first_choice,
+    mark_safe_lazy,
+)
 
 from .constants import (
-    GRID_COLUMN_ALIGNMENT_CHOICES, GRID_COLUMN_CHOICES, GRID_CONTAINER_CHOICES, GRID_ROW_HORIZONTAL_ALIGNMENT_CHOICES,
-    GRID_ROW_VERTICAL_ALIGNMENT_CHOICES, GRID_SIZE,
+    GRID_COLUMN_ALIGNMENT_CHOICES,
+    GRID_COLUMN_CHOICES,
+    GRID_CONTAINER_CHOICES,
+    GRID_ROW_HORIZONTAL_ALIGNMENT_CHOICES,
+    GRID_ROW_VERTICAL_ALIGNMENT_CHOICES,
+    GRID_SIZE,
 )
 
 
@@ -21,15 +30,18 @@ class Bootstrap4GridContainer(CMSPlugin):
     Layout > Grid: "Container" Plugin
     https://getbootstrap.com/docs/4.0/layout/grid/
     """
+
     container_type = models.CharField(
-        verbose_name=_('Container type'),
+        verbose_name=_("Container type"),
         choices=GRID_CONTAINER_CHOICES,
         default=get_first_choice(GRID_CONTAINER_CHOICES),
         max_length=255,
-        help_text=mark_safe_lazy(_(
-            'Defines if the grid should use fixed width (<code>.container</code>) '
-            'or fluid width (<code>.container-fluid</code>).'
-        )),
+        help_text=mark_safe_lazy(
+            _(
+                "Defines if the grid should use fixed width (<code>.container</code>) "
+                "or fluid width (<code>.container-fluid</code>)."
+            )
+        ),
     )
     tag_type = TagTypeField()
     attributes = AttributesField()
@@ -39,7 +51,7 @@ def __str__(self):
 
     def get_short_description(self):
         choice = get_choices_match(GRID_CONTAINER_CHOICES, self.container_type)
-        return f'({choice})'
+        return f"({choice})"
 
 
 class Bootstrap4GridRow(CMSPlugin):
@@ -47,30 +59,37 @@ class Bootstrap4GridRow(CMSPlugin):
     Layout > Grid: "Row" Plugin
     https://getbootstrap.com/docs/4.0/layout/grid/
     """
+
     vertical_alignment = models.CharField(
-        verbose_name=_('Vertical alignment'),
+        verbose_name=_("Vertical alignment"),
         choices=GRID_ROW_VERTICAL_ALIGNMENT_CHOICES,
         blank=True,
         max_length=255,
-        help_text=mark_safe_lazy(_(
-            'Read more in the <a href="{link}" target="_blank">documentation</a>.')
-                .format(link='https://getbootstrap.com/docs/4.0/layout/grid/#vertical-alignment')
+        help_text=mark_safe_lazy(
+            _(
+                'Read more in the <a href="{link}" target="_blank">documentation</a>.'
+            ).format(
+                link="https://getbootstrap.com/docs/4.0/layout/grid/#vertical-alignment"
+            )
         ),
     )
     horizontal_alignment = models.CharField(
-        verbose_name=_('Horizontal alignment'),
+        verbose_name=_("Horizontal alignment"),
         choices=GRID_ROW_HORIZONTAL_ALIGNMENT_CHOICES,
         blank=True,
         max_length=255,
-        help_text=mark_safe_lazy(_(
-            'Read more in the <a href="{link}" target="_blank">documentation</a>.')
-                .format(link='https://getbootstrap.com/docs/4.0/layout/grid/#horizontal-alignment')
+        help_text=mark_safe_lazy(
+            _(
+                'Read more in the <a href="{link}" target="_blank">documentation</a>.'
+            ).format(
+                link="https://getbootstrap.com/docs/4.0/layout/grid/#horizontal-alignment"
+            )
         ),
     )
     gutters = models.BooleanField(
-        verbose_name=_('Remove gutters'),
+        verbose_name=_("Remove gutters"),
         default=False,
-        help_text=_('Removes the marginal gutters from the grid.'),
+        help_text=_("Removes the marginal gutters from the grid."),
     )
     tag_type = TagTypeField()
     attributes = AttributesField()
@@ -80,11 +99,9 @@ def __str__(self):
 
     def get_short_description(self):
         column_count = len(self.child_plugin_instances or [])
-        column_count_str = ungettext(
-            '(1 column)',
-            '(%(count)i columns)',
-            column_count
-        ) % {'count': column_count}
+        column_count_str = ngettext(
+            "(1 column)", "(%(count)i columns)", column_count
+        ) % {"count": column_count}
 
         return column_count_str
 
@@ -94,15 +111,16 @@ class Bootstrap4GridColumn(CMSPlugin):
     Layout > Grid: "Column" Plugin
     https://getbootstrap.com/docs/4.0/layout/grid/
     """
+
     column_type = models.CharField(
-        verbose_name=_('Column type'),
+        verbose_name=_("Column type"),
         choices=GRID_COLUMN_CHOICES,
         default=GRID_COLUMN_CHOICES[0][0],
         blank=True,
         max_length=255,
     )
     column_alignment = models.CharField(
-        verbose_name=_('Alignment'),
+        verbose_name=_("Alignment"),
         choices=GRID_COLUMN_ALIGNMENT_CHOICES,
         blank=True,
         max_length=255,
@@ -114,33 +132,35 @@ def __str__(self):
         return str(self.pk)
 
     def get_short_description(self):
-        text = ''
+        text = ""
         classes = self.get_grid_values()
         if self.xs_col:
-            text += f'(col-{self.xs_col}) '
+            text += f"(col-{self.xs_col}) "
         else:
-            text += '(auto) '
-        if self.column_type != 'col':
-            text += f'.{self.column_type} '
+            text += "(auto) "
+        if self.column_type != "col":
+            text += f".{self.column_type} "
         if classes:
-            text += '.{}'.format(' .'.join(self.get_grid_values()))
+            text += ".{}".format(" .".join(self.get_grid_values()))
         return text
 
     def get_grid_values(self):
         classes = []
         for device in DEVICE_SIZES:
-            for element in ('col', 'order', 'offset', 'ml', 'mr'):
-                size = getattr(self, f'{device}_{element}')
-                if isinstance(size, int) and (element == 'col' or element == 'order' or element == 'offset'):
-                    if device == 'xs':
-                        classes.append(f'{element}-{int(size)}')
+            for element in ("col", "order", "offset", "ml", "mr"):
+                size = getattr(self, f"{device}_{element}")
+                if isinstance(size, int) and (
+                    element == "col" or element == "order" or element == "offset"
+                ):
+                    if device == "xs":
+                        classes.append(f"{element}-{int(size)}")
                     else:
-                        classes.append(f'{element}-{device}-{int(size)}')
+                        classes.append(f"{element}-{device}-{int(size)}")
                 elif size:
-                    if device == 'xs':
-                        classes.append('{}-{}'.format(element, 'auto'))
+                    if device == "xs":
+                        classes.append("{}-{}".format(element, "auto"))
                     else:
-                        classes.append('{}-{}-{}'.format(element, device, 'auto'))
+                        classes.append("{}-{}-{}".format(element, device, "auto"))
 
         return classes
 
@@ -162,26 +182,26 @@ def get_grid_values(self):
 for size in DEVICE_SIZES:
     # Grid size
     Bootstrap4GridColumn.add_to_class(
-        f'{size}_col',
+        f"{size}_col",
         IntegerRangeFieldPartial(),
     )
     # Grid ordering
     Bootstrap4GridColumn.add_to_class(
-        f'{size}_order',
+        f"{size}_order",
         IntegerRangeFieldPartial(),
     )
     # Grid offset
     Bootstrap4GridColumn.add_to_class(
-        f'{size}_offset',
+        f"{size}_offset",
         IntegerRangeFieldPartial(),
     )
     # Grid margin left (ml)
     Bootstrap4GridColumn.add_to_class(
-        f'{size}_ml',
+        f"{size}_ml",
         BooleanFieldPartial(),
     )
     # Grid margin right (ml)
     Bootstrap4GridColumn.add_to_class(
-        f'{size}_mr',
+        f"{size}_mr",
         BooleanFieldPartial(),
     )
diff --git a/tests/requirements/base.txt b/tests/requirements/base.txt
index 66157f2..68fb1e6 100644
--- a/tests/requirements/base.txt
+++ b/tests/requirements/base.txt
@@ -7,3 +7,4 @@ isort
 flake8
 pyflakes>=2.1
 wheel
+django-filer<3