docs: def set_up():
      """
      Set ups the V8 machinery:\
      platform, VM and context.
  
      This function is not thread-safe,\
      it must be called from a place\
      where is guaranteed it will be\
      called once and only once.\
      Probably within the main-thread\
      at import time.
      """
      global _context
  
      if _context is not None:
          raise AssertionError(
              'This function must only be called '
              'once in an application lifetime')
  
      platform.set_up()
      vm = platform.create_vm()
      vm.set_up()
      _context = vm.create_context()
      _context.set_up()
      atexit.register(_tear_down)