code: def load_lib():
      global _itk, _read_function, _write_function
      try:
          import itk as _itk
  
          _read_function = _itk.imread
          _write_function = _itk.imwrite
      except ImportError:
          try:
              import SimpleITK as _itk
  
              _read_function = _itk.ReadImage
              _write_function = _itk.WriteImage
          except ImportError:
              raise ImportError(
                  "itk could not be found. "
                  "Please try "
                  "  python -m pip install itk "
                  "or "
                  "  python -m pip install simpleitk "
                  "or refer to "
                  "  https://itkpythonpackage.readthedocs.io/ "
                  "for further instructions."
              )
      return _itk
  
imports: from ..core import Format, has_module
label_desc: Use image node_id 1 for calling a global function with example usage: load_lib() and returns: _itk