try catch import to support less than v5

djangoql/schema.py

@@ -8,14 +8,18 @@
 from django.core.exceptions import FieldDoesNotExist
 from django.db import models
 from django.db.models import ManyToManyRel, ManyToOneRel
-from django.db.models.fields.generated import GeneratedField
 from django.db.models.fields.related import ForeignObjectRel
 from django.utils.timezone import get_current_timezone
 
 from .ast import Comparison, Const, List, Logical, Name, Node
 from .compat import text_type
 from .exceptions import DjangoQLSchemaError
 
+try:
+    from django.db.models.fields.generated import GeneratedField  # Django >= 5.0
+except ImportError:
+    GeneratedField = None
+
 
 class DjangoQLField(object):
     """