code: def check_forward(self, x, kh, kw, sy, sx, ph, pw, dy, dx, gpu):
      x = x.copy()
      n, c, h, w = x.shape
      col = functions.im2col(
          x, (kh, kw), (sy, sx), (ph, pw), dilate=(dy, dx)
      ).data
      col_h = get_conv_outsize(h, kh, sy, ph, d=dy)
      col_w = get_conv_outsize(w, kw, sx, pw, d=dx)
  
      self.assertEqual(col.shape, (n, c * kh * kw, col_h, col_w))
      col = col.reshape(n, c, kh, kw, col_h, col_w)
      col = cuda.to_cpu(col)
  
      for y in moves.range(col_h):
          for x in moves.range(col_w):
              for ky in moves.range(kh):
                  for kx in moves.range(kw):
                      oy = y * sy - ph + ky * dy
                      ox = x * sx - pw + kx * dx
                      if 0 <= oy < h and 0 <= ox < w:
                          testing.assert_allclose(
                              col[:, :, ky, kx, y, x],
                              self.x[:, :, oy, ox],
                          )
                      else:
                          testing.assert_allclose(
                              col[:, :, ky, kx, y, x],
                              numpy.zeros((2, 3), self.dtype),
                          )
  
imports: import unittest
  import numpy
  from six import moves
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer.utils.conv import get_conv_outsize
label_desc: Use image node_id 2 for calling the TestIm2ColForward obj's underlying member method code with example usage: obj.check_forward(x, kh, kw, sy, sx, ph, pw, dy, dx, gpu) without return types