def METHOD_NAME(self):
    mock_os_open = mock.mock_open(read_data='mlx-wdt-main')
    with mock.patch('sonic_platform.watchdog.open', mock_os_open):
        assert is_mlnx_wd_main('')
    mock_os_open = mock.mock_open(read_data='invalid')
    with mock.patch('sonic_platform.watchdog.open', mock_os_open):
        assert not is_mlnx_wd_main('')
    mock_os_open.side_effect = IOError
    with mock.patch('sonic_platform.watchdog.open', mock_os_open):
        assert not is_mlnx_wd_main('')