class_docstr: Im2Col function.
code: def forward(self, inputs):
      (x,) = inputs
      y = _im2col(
          x,
          self.kh,
          self.kw,
          self.sy,
          self.sx,
          self.ph,
          self.pw,
          cover_all=self.cover_all,
          dy=self.dy,
          dx=self.dx,
      )
      n, c, kh, kw, out_h, out_w = y.shape
      return (y.reshape(n, c * kh * kw, out_h, out_w),)
  
imports: import numpy
  from chainer import function_node
  from chainer.utils.conv import col2im_cpu
  from chainer.utils.conv import col2im_gpu
  from chainer.utils.conv import im2col_cpu
  from chainer.utils.conv import im2col_gpu
  from chainer.utils import type_check
label_desc: Use image node_id 3 for calling the Im2Col obj's underlying member method code with example usage: obj.forward(inputs) and returns: y