Revert not needed black check.

tests/model_fields_/test_objectidfield.py

@@ -1,13 +1,9 @@
-import shutil
-
 from bson import ObjectId
 from django.core import exceptions
 from django.test import SimpleTestCase
 
 from django_mongodb.fields import ObjectIdField
 
-HAS_BLACK = shutil.which("black")
-
 
 class MethodTests(SimpleTestCase):
     def test_deconstruct(self):
@@ -33,9 +29,6 @@ def test_to_python(self):
     def test_to_python_invalid_value(self):
         for invalid_value in [3, "None", {}, []]:
             with self.subTest(invalid_value=invalid_value):
-                if HAS_BLACK:
-                    msg = f'["“{invalid_value}” value must be an Object Id."]'
-                else:
-                    msg = f"['“{invalid_value}” value must be an Object Id.']"
+                msg = f"['“{invalid_value}” value must be an Object Id.']"
                 with self.assertRaisesMessage(exceptions.ValidationError, msg):
                     ObjectIdField().to_python(invalid_value)