code: def test_use_foreground():
      """Test that a foreground box is returned when required (prob=1) and possible (fixed data)"""
      for classes, weights, bg in [
          (None, None, None),
          (None, None, 1),
          ([1, 2, 3], None, None),
          (None, [1, 1, 1], None),
          (None, [1, 1, 1], 0),
          ([1, 2, 3], [1, 1, 1], None),
      ]:
          yield _test_use_foreground, classes, weights, bg
  
imports: from nose_utils import assert_raises
  import nvidia.dali
  import nvidia.dali.fn
  import nvidia.dali.ops
  import numpy
  import scipy.ndimage
  import scipy.ndimage.measurements
  import random
  from test_utils import check_batch, np_type_to_dali
  from nose.tools import nottest
  from nose.plugins.attrib import attr
label_desc: Use image node_id 4 for calling a global function with example usage: test_use_foreground() without return types