code: def test_histogram(self, xp, scp, dtype):
      nbins = 5
      minval = 0
      maxval = 10
      image = self._make_image(self.shape, xp, dtype, scale=maxval)
      labels = self.labels
      index = self.index
      if labels is not None:
          labels = testing.shaped_random(
              self.shape, xp, dtype=xp.int32, scale=self.labels
          )
      if index is not None:
          index = xp.array(index)
      op = getattr(scp.ndimage, "histogram")
      if index is not None and labels is None:
          # cannot give an index array without labels
          with pytest.raises(ValueError):
              op(image, minval, maxval, nbins, labels, index)
          return xp.asarray([])
      result = op(image, minval, maxval, nbins, labels, index)
      if index is None:
          return result
      # stack 1d arrays into a single array for comparison
      return xp.stack(result)
  
imports: import sys
  import warnings
  import numpy
  import pytest
  import cupy
  from cupy.cuda import runtime
  from cupy import testing
  from cupy import _util
  from cupy._core import _accelerator
  import cupyx.scipy.ndimage
label_desc: Use image node_id 2 for calling the TestHistogram obj's underlying member method code with example usage: obj.test_histogram(xp, scp, dtype) and returns: xp, xp, result