Error expected str, bytes or os.PathLike object, not NoneType

[aymalkhalid]

I am using promptify for solving NER Problem everything works fine except sometimes when it returns an Error for Nonetype which means it's empty but on the exception I am also passing it as a plain string but still same error.
It works fine after pausing for 1 minute or more but again it returns NoneType when I am testing it for continous requests.

from promptify.models.nlp.openai_model import OpenAI
from promptify.prompts.nlp.prompter import Prompter


try:
    model = OpenAI(openai.api_key)
except Exception as e:
    print("Error",e)
    model = OpenAI("me-2asdasdasdT123123.........")

#Initialize Prompter
nlp_prompter = Prompter(model)
ner_result = nlp_prompter.fit('ner.jinja',
                        domain      = 'Hospitality',
                        text_input=str('My name is Aymal'),
                        description= "The API response below contains user name"
                        )
 print("NER RESULT",ner_result)