code: def test_invalid_reference():
      NLDaliPipeline("cpu", None, 1, reference=0.0).build()
  
imports: from nvidia.dali.pipeline import Pipeline
  import nvidia.dali.ops
  import numpy
  from functools import partial
  from test_utils import compare_pipelines
  from test_utils import RandomDataIterator
  from nose_utils import raises
label_desc: Use image node_id 7 for calling a global function with example usage: test_invalid_reference() without return types