>>> print(json.dumps({'kernel_version': '1.2', 'test_kernel_versions': [('test2', 'reboot_to_backport', '1.3~utopic')]}, indent=2))
{
  "kernel_version": "1.2",
  "test_kernel_versions": [
    [
      "test2",
      "reboot_to_backport",
      "1.3~utopic"
    ]
  ]
}