code: def cache_key(model, pk):
      "Generates a cache key for a model instance."
      app = model._meta.app_label
      name = model._meta.module_name
      return 'api:{0}:{1}:{2}'.format(app, name, pkf cache_key(model, pk):
      "Generates a cache key for a model instance."
      app = model._meta.app_label
      name = model._meta.module_name
      return 'api:{0}:{1}:{2}'.format(app, name, pk)
docs: Generates a cache key for a model instance.