'<' not supported between instances of 'NoneType' and 'str' error coming while training chatbot

Question

I am working with yaml file for training of my chatbot data. But while executing training command it is giving me domain syntax error or it's showing that it is not a valid yaml.

Commmand used for training is:

rasa train

Below is the file for which it is giving error :

domain.yml

session_config: 
  carry_over_slots_to_new_session: true
  session_expiration_time: 60
actions: 
  - utter_loing_info
  - utter_already_logged_out_meesage
  - utter_end_date_greater_than_start_date
  - action_reset_form_slots
entities: 
  - single_day_leave_date
  - start_date
forms: 
  - login_form
  - apply_leave_form
  - 
intents: 
  - 
    login: 
      use_entities: false
  - leav_apply
  - apply_cl
  - apply_lwp
  - leav_status
  - stop
responses: 
  utter_ask_single_day_leave_date: 
    - 
      text: "tell me date for which you want to apply."
  utter_ask_start_date: 
    - 
      text: "Could you please help me with leave start date[DD-MM-YYYY]?"

slots: 
    purpose: 
    auto_fill: false
    type: unfeaturized
  single_day_leave_date: 
    auto_fill: false
    type: unfeaturized
  start_date: 
    auto_fill: false
    type: unfeaturized

Below is the error description :

2020-04-09 12:35:54.723143: W tensorflow/stream_executor/platform/default/dso_loader.cc:55] Could not load dynamic library 'cudart64_101.dll'; dlerror: cudart64_101.dll not found 
2020-04-09 12:35:55.047696: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
Traceback (most recent call last):
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\Prashant Kamble\AppData\Local\Programs\Python\Python37\Scripts\rasa.exe\__main__.py", line 7, in <module>
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\__main__.py", line 91, in main
    cmdline_arguments.func(cmdline_arguments)
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\cli\train.py", line 76, in train
    additional_arguments=extract_additional_arguments(args),
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\train.py", line 50, in train
    additional_arguments=additional_arguments,
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\asyncio\base_events.py", line 579, in run_until_complete
    return future.result()
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\train.py", line 88, in train_async
    domain = await file_importer.get_domain()
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\importers\importer.py", line 242, in get_domain
    domains = await asyncio.gather(*domains)
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\importers\rasa.py", line 66, in get_domain
    domain = Domain.load(self._domain_path)
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\core\domain.py", line 101, in load
    domain = domain.merge(other)
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\core\domain.py", line 250, in merge
    combined[key] = merge_lists(combined[key], domain_dict[key])
  File "c:\users\prashant kamble\appdata\local\programs\python\python37\lib\site-packages\rasa\core\domain.py", line 228, in merge_lists
    return sorted(list(set(l1 + l2)))
TypeError: '<' not supported between instances of 'NoneType' and 'str'

Answer 1

I think that I missed the string infront of my - dash sign.

forms: 
  - login_form
  - apply_leave_form
  - 

It should be like below sample:

forms: 
  - login_form
  - apply_leave_form
  - demo_form