code: def window_reverse(windows, window_size, H, W):
      """
      Args:
          windows: (num_windows*B, window_size, window_size, C)
          window_size (int): Window size
          H (int): Height of image
          W (int): Width of image
      Returns:
          x: (B, H, W, C)
      """
      _, _, _, C = windows.shape
      B = int(windows.shape[0] / (H * W / window_size / window_size))
      x = windows.reshape(
          [
              -1,
              H // window_size,
              W // window_size,
              window_size,
              window_size,
              C,
          ]
      )
      x = x.transpose([0, 1, 3, 2, 4, 5]).reshape([-1, H, W, C])
      return x
  
imports: import numpy
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from ppdet.modeling.shape_spec import ShapeSpec
  from ppdet.core.workspace import register, serializable
  from .transformer_utils import DropPath, Identity
  from .transformer_utils import add_parameter, to_2tuple
  from .transformer_utils import ones_, zeros_, trunc_normal_
label_desc: Use image node_id 2 for calling a global function with example usage: window_reverse(windows, window_size, H, W) and returns: x