Error on calling delete method on object in django

Question

I have a stage model defined as below. When I try to perform delete operation I am getting below error. For other models, delete is working fine. previously I have been using django 2.2. After Upgrade I am seeing this error.

from djangodeletes.softdeletes import (
    SoftDeletable,
    SoftDeleteManager,
    SoftDeleteQuerySet,
)

class Stage(SoftDeletable, models.Model):
    name = models.CharField(max_length=50)
    stage_type = models.CharField(
        choices=STAGE_TYPE_CHOICES,
        null=True,
        blank=True,
        max_length=50,
    )
    close_stage_type = models.CharField(
        choices=CLOSE_STAGE_TYPE,
        null=True,
        blank=True,
        max_length=20,
    )
    sequence = models.IntegerField(null=True, blank=True)
    pipeline = models.ForeignKey(
        Pipeline,
        null=True,
        blank=True,
        on_delete=models.CASCADE,
        related_name="pipeline_stages",
    )
    created_by = models.ForeignKey(
        "accounts.User",
        on_delete=models.SET_NULL,
        null=True,
        related_name="stage_created_by",
    )

    modified_by = models.ForeignKey(
        "accounts.User",
        on_delete=models.SET_NULL,
        null=True,
        related_name="stage_modified_by",
    )

    created_at = models.DateTimeField(auto_now_add=True)
    modified_at = models.DateTimeField(auto_now=True)

    objects = SoftDeleteManager.from_queryset(SoftDeleteQuerySet)()

    def __str__(self):
        return str(self.id)

Stage.objects.get(id = 1240).delete()

  File "/home/srinivas/design_studio_app_1/design_studio_app/prac.py", line 50, in <module>
    stage.delete()
  File "/home/srinivas/design_studio_app_1/.venv/lib/python3.8/site-packages/djangodeletes/softdeletes/models.py", line 78, in delete
    for (field, value), instances in instances_for_fieldvalues.items():
AttributeError: 'list' object has no attribute 'items'```

I am using below versions

Python 3.8.18, Django 4.2.9, djangodeletes 0.43

what could be the issue?