class_docstr: Twins Vision Transfomer (Revisiting Spatial Attention)
  
  Adapted from PVT (PyramidVisionTransformer) class at https://github.com/whai362/PVT.git
code: def set_grad_checkpointing(self, enable=True):
      assert not enable, "gradient checkpointing not supported"
  
imports: import math
  from functools import partial
  from typing import Tuple
  import torch
  import torch.nn
  import torch.nn.functional
  from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
  from timm.layers import Mlp, DropPath, to_2tuple, trunc_normal_, use_fused_attn
  from ._builder import build_model_with_cfg
  from ._features_fx import register_notrace_module
  from ._registry import register_model, generate_default_cfgs
  from .vision_transformer import Attention
label_desc: Use image node_id 4 for calling the Twins obj's underlying member method code with example usage: obj.set_grad_checkpointing(enable) without return types