code: def pixel_unshuffle(x, scale):
      """Pixel unshuffle.
      Args:
          x (Tensor): Input feature with shape (b, c, hh, hw).
          scale (int): Downsample ratio.
      Returns:
          Tensor: the pixel unshuffled feature.
      """
      b, c, hh, hw = x.size()
      out_channel = c * (scale**2)
      assert hh % scale == 0 and hw % scale == 0
      h = hh // scale
      w = hw // scale
      x_view = x.view(b, c, h, scale, w, scale)
      return x_view.permute(0, 1, 3, 5, 2, 4).reshape(
          b, out_channel, h, w
      )
  
imports: from collections import OrderedDict
  import math
  import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling a global function with example usage: pixel_unshuffle(x, scale) and returns: x_view