title: How to specify multiple models to train object detector with HPO using gluonCV auto task?
body: <p>I'm kinda new to this. I'm trying to use gluoncv auto object detection module by specifying different models in the search space (Hyper parameter tuning) Reference: <a href="https://cv.gluon.ai/build/examples_auto_module/demo_auto_detection.html" rel="nofollow noreferrer">https://cv.gluon.ai/build/examples_auto_module/demo_auto_detection.html</a></p>
  <pre><code>from gluoncv.auto.tasks.object_detection import ObjectDetection
  import autogluon.core as ag
  
  train = ObjectDetection.Dataset.from_voc(
      'https://autogluon.s3.amazonaws.com/datasets/tiny_motorbike.zip')
  train, val, test = train.random_split(val_size=0.1, test_size=0.1)
  
  time_limits = 60 * 60  # 1hr
  
  search_args = {'lr': ag.Categorical(1e-3, 1e-2),
                 'num_trials': 4,
                 'epochs': 10,
                 'num_workers': 16,
                 'batch_size': 4,
                 'ngpus_per_trial': 1,
                 'search_strategy': 'random',
                 'time_limits': time_limits}
  
  
  task = ObjectDetection(search_args)
  detector = task.fit(train, val)
  </code></pre>
  <p>I want to specify models in the above search_args(search arguments) like center_net_resnet50_v1b_coco,faster_rcnn_resnet50_v1b_coco etc (or similar models from mxnet). How to add this choice in the search arguments so that it returns the best model for the specified dataset?
  reference link: <a href="https://cv.gluon.ai/build/examples_auto_module/demo_auto_detection.html" rel="nofollow noreferrer">https://cv.gluon.ai/build/examples_auto_module/demo_auto_detection.html</a></p>