text: _base_ = [
      '../_base_/models/retinanet_r50_fpn.py', '../common/mstrain_3x_coco.py'
  ]
  # optimizer
  model = dict(
      pretrained='open-mmlab://resnext101_64x4d',
      backbone=dict(type='ResNeXt', depth=101, groups=64, base_width=4))
  optimizer = dict(type='SGD', lr=0.01)