class_docstr: A basic Swin Transformer layer for one stage.
  
  Args:
      dim (int): Number of input channels.
      input_resolution (tuple[int]): Input resolution.
      depth (int): Number of blocks.
      num_heads (int): Number of attention heads.
      window_size (int): Local window size.
      mlp_ratio (float): Ratio of mlp hidden dim to embedding dim.
      qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True
      qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set.
      drop (float, optional): Dropout rate. Default: 0.0
      attn_drop (float, optional): Attention dropout rate. Default: 0.0
      drop_path (float | tuple[float], optional): Stochastic depth rate. Default: 0.0
      norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
      downsample (nn.Module | None, optional): Downsample layer at the end of the layer. Default: None
      use_checkpoint (bool): Whether to use checkpointing to save memory. Default: False.
code: def flops(self):
      flops = 0
      for blk in self.blocks:
          flops += blk.flops()
      if self.downsample is not None:
          flops += self.downsample.flops()
      return flops
  
imports: from typing import List, Optional
  import torch
  import torch.nn
  import torch.utils.checkpoint
  from vissl.config import AttrDict
  from vissl.models.model_helpers import DropPath, to_2tuple, trunc_normal_
  from vissl.models.trunks import register_model_trunk
label_desc: Use image node_id 4 for calling the BasicLayer obj's underlying member method code with example usage: obj.flops() and returns: flops