code: def axes2names(axes, layout="abcdefghijklmnopqrstuvwxyz"):
      return "".join([layout[axis] for axis in axes])
  
imports: from nvidia.dali.pipeline import Pipeline
  from nvidia.dali import backend
  import nvidia.dali.ops
  import numpy
  from test_utils import dali_type
  from nvidia.dali import fn, pipeline_def, types
  from nose2.tools import params
label_desc: Use image node_id 18 for calling a global function with example usage: axes2names(axes, layout) and returns: str