code: def mc3_18_flow(pretrained=False, progress=True, **kwargs):
      """Constructor for 18 layer Mixed Convolution network for optical flow."""
  
      return _video_resnet_flow(
          "mc3_18",
          pretrained,
          progress,
          block=BasicBlock,
          conv_makers=[Conv3DSimple] + [Conv3DNoTemporal] * 3,
          layers=[2, 2, 2, 2],
          stem=BasicFLowStem,
          **kwargs,
      )
  
imports: import torch.nn
  from torch.hub import load_state_dict_from_url
label_desc: Use image node_id 6 for calling a global function with example usage: mc3_18_flow(pretrained, progress) and returns: _video_resnet_flow