code: def test_neibs_half_step_by_valid(self):
      neib_shapes = ((3, 3), (3, 5), (5, 3))
      for shp_idx, (shape, neib_step) in enumerate(
          [
              [(7, 8, 5, 5), (1, 1)],
              [(7, 8, 5, 5), (2, 2)],
              [(7, 8, 5, 5), (4, 4)],
              [(7, 8, 5, 5), (1, 4)],
              [(7, 8, 5, 5), (4, 1)],
              [(80, 90, 5, 5), (1, 2)],
              [(1025, 9, 5, 5), (2, 1)],
              [(1, 1, 5, 1037), (2, 4)],
              [(1, 1, 1045, 5), (4, 2)],
          ]
      ):
          for neib_shape in neib_shapes:
              for dtype in self.dtypes:
                  x = theano.shared(
                      np.random.randn(*shape).astype(dtype)
                  )
                  extra = (neib_shape[0] // 2, neib_shape[1] // 2)
                  padded_shape = (
                      x.shape[0],
                      x.shape[1],
                      x.shape[2] + 2 * extra[0],
                      x.shape[3] + 2 * extra[1],
                  )
                  padded_x = T.zeros(padded_shape)
                  padded_x = T.set_subtensor(
                      padded_x[
                          :,
                          :,
                          extra[0] : -extra[0],
                          extra[1] : -extra[1],
                      ],
                      x,
                  )
                  x_using_valid = images2neibs(
                      padded_x, neib_shape, neib_step, mode="valid"
                  )
                  x_using_half = images2neibs(
                      x, neib_shape, neib_step, mode="half"
                  )
                  f_valid = theano.function(
                      [], x_using_valid, mode="FAST_RUN"
                  )
                  f_half = theano.function(
                      [], x_using_half, mode=self.mode
                  )
                  unittest_tools.assert_allclose(f_valid(), f_half())
  
imports: from __future__ import absolute_import, print_function, division
  import numpy
  import unittest
  import theano
  from theano import shared, function
  import theano.tensor
  from theano.tensor.nnet.neighbours import images2neibs, neibs2images, Images2Neibs
  from theano.tests import unittest_tools
  from theano import change_flags
label_desc: Use image node_id 6 for calling the T_Images2Neibs obj's underlying member method code with example usage: obj.test_neibs_half_step_by_valid() without return types