text: from cc import LuaException, import_file, pocket, peripheral
  
  _lib = import_file('_lib.py', __file__)
  
  
  assert peripheral.isPresent('back') is False
  
  tbl = _lib.get_object_table('pocket')
  assert _lib.get_class_table(pocket) == tbl
  
  _lib.step('Clean inventory from any pocket upgrades')
  
  with _lib.assert_raises(LuaException):
      pocket.equipBack()
  with _lib.assert_raises(LuaException):
      pocket.unequipBack()
  assert peripheral.isPresent('back') is False
  
  _lib.step('Put any pocket upgrade to inventory')
  
  assert pocket.equipBack() is None
  assert peripheral.isPresent('back') is True
  
  assert pocket.unequipBack() is None
  assert peripheral.isPresent('back') is False
  
  print('Test finished successfully')
  