class_docstr: Generates a NetworkX graph containing nodes at the centroid of each region in the input ROI file.
  Node data is added from the resolution network file.
  
  Example
  -------
  
  >>> import nipype.interfaces.cmtk as cmtk
  >>> mknode = cmtk.CreateNodes()
  >>> mknode.inputs.roi_file = 'ROI_scale500.nii.gz'
  >>> mknode.run() # doctest: +SKIP
code: def _list_outputs(self):
      outputs = self._outputs().get()
      outputs["node_network"] = op.abspath(self.inputs.out_filename)
      return outputs
  
imports: import pickle
  import os.path
  import numpy
  import nibabel
  import networkx
  from ...None import logging
  from ...utils.filemanip import split_filename
  from ..base import BaseInterface, BaseInterfaceInputSpec, traits, File, TraitedSpec, Directory, OutputMultiPath, isdefined
label_desc: Use image node_id 2 for calling the CreateNodes obj's underlying member method code with example usage: obj._list_outputs() and returns: outputs