new_contents: """
  Small Python 2/3 compatibility layer.
  """
  
  import sys
  
  
  if sys.version_info[0] == 3:
  
    exec_ = exec
  
    def reraise(tp, value, tb=None):
      if value is None:
        value = tp()
      if value.__traceback__ is not tb:
        raise value.with_traceback(tb)
      raise value
  
  
  else:
  
    def exec_(_code_, _globs_=None, _locs_=None):
      """Execute code in a namespace."""
      if _globs_ is None:
        frame = sys._getframe(1)
        _globs_ = frame.f_globals
        if _locs_ is None:
          _locs_ = frame.f_locals
        del frame
      elif _locs_ is None:
        _locs_ = _globs_
      exec("""exec _code_ in _globs_, _locs_""")
  
    exec_("def reraise(tp, value, tb=None):\n"
          "  raise tp, value, tb")
  
subject: add nodepy.utils.compat