cleanup unused imports and extra line

netbox/dcim/api/views.py

@@ -1,5 +1,4 @@
 from django.contrib.contenttypes.prefetch import GenericPrefetch
-from django.db.models import Prefetch
 from django.http import Http404, HttpResponse
 from django.shortcuts import get_object_or_404
 from drf_spectacular.types import OpenApiTypes

netbox/dcim/models/cables.py

@@ -1,5 +1,4 @@
 import itertools
-from collections import defaultdict
 
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.core.exceptions import ValidationError

netbox/utilities/generics/field.py

@@ -140,4 +140,3 @@ class GenericArrayForeignKey(FieldCacheMixin, Field):
             data.append(rel_objects)
         self.set_cached_value(instance, data)
         return data
-