docstr: Creates the module for the given stage
  Args:
      fusion_dim_in (int): input stage dimension
      stage_idx (int): which stage this is
docstr_tok: ["Creates","the","module","for","the","given","stage","Args",":","fusion_dim_in","(","int",")",":","input","stage","dimension","stage_idx","(","int",")",":","which","stage","this","is"]
code: def create_module(
      self, fusion_dim_in: int, stage_idx: int
  ) -> nn.Module:
      """
      Creates the module for the given stage
      Args:
          fusion_dim_in (int): input stage dimension
          stage_idx (int): which stage this is
      """
      if stage_idx > self.max_stage_idx:
          return nn.Identity()
  
      conv_dim_in = (
          fusion_dim_in // self.slowfast_channel_reduction_ratio
      )
      conv_fast_to_slow = nn.Conv3d(
          conv_dim_in,
          int(conv_dim_in * self.conv_fusion_channel_ratio),
          kernel_size=self.conv_kernel_size,
          stride=self.conv_stride,
          padding=[k_size // 2 for k_size in self.conv_kernel_size],
          bias=False,
      )
      norm_module = (
          None
          if self.norm is None
          else self.norm(
              num_features=conv_dim_in * self.conv_fusion_channel_ratio,
              eps=self.norm_eps,
              momentum=self.norm_momentum,
          )
      )
      activation_module = (
          None if self.activation is None else self.activation()
      )
      return FuseFastToSlow(
          conv_fast_to_slow=conv_fast_to_slow,
          norm=norm_module,
          activation=activation_module,
      )
  
imports: from typing import Callable, List, Optional, Tuple, Union
  import torch
  import torch.nn
  from pytorchvideo.layers.utils import set_attributes
  from pytorchvideo.models.head import create_res_basic_head, create_res_roi_pooling_head
  from pytorchvideo.models.net import DetectionBBoxNetwork, MultiPathWayWithFuse, Net
  from pytorchvideo.models.resnet import create_bottleneck_block, create_res_stage
  from pytorchvideo.models.stem import create_res_basic_stem
label_desc: Use image node_id 2 for calling the FastToSlowFusionBuilder obj's underlying member method code with example usage: obj.create_module(fusion_dim_in, stage_idx) and returns: FuseFastToSlow, nn