UniqueViolation: duplicate key value violates unique constraint "unique_link_trace_item_user"
DETAIL:  Key (user_id, item_id)=(xxx, yyy) already exists.
  File "django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
  File "psycopg/cursor.py", line 117, in execute
    raise ex.with_traceback(None)

IntegrityError: duplicate key value violates unique constraint "unique_link_trace_item_user"
DETAIL:  Key (user_id, item_id)=(xxx, yyy) already exists.
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...
  File "core/api/viewsets.py", line 550, in retrieve
    models.LinkTrace.objects.create(item=instance, user=request.user)
  File "core/models.py", line 133, in save
    super().save(*args, **kwargs)