code: def vtk_old():
      """Checks if VTK uses the old-style pipeline (VTK<6.0)"""
      global _vtk_version
      if _vtk_version is None:
          raise RuntimeException("VTK is not correctly installed.")
      return _vtk_version[0] < 6
  
file_path: nipype/nipype/interfaces/vtkbase.py
imports: import os
  from ..None import logging
label_desc: Use image node_id 4 for calling a global function with example usage: vtk_old() and returns: unknown