code: def vtk_version():
      """Get VTK version"""
      global _vtk_version
      return _vtk_version
  
file_path: nipype/nipype/interfaces/vtkbase.py
imports: import os
  from ..None import logging
label_desc: Use image node_id 1 for calling a global function with example usage: vtk_version() and returns: _vtk_version