from PyInquirer import prompt, Validator, ValidationError from prompt_toolkit import document import regex class NickNameValidator(Validator): def validate(self, document: document.Document) -> None: ok = regex.match('^[A-Z][a-z]+$', document.text) if not ok: raise ValidationError(message = 'Please enter a correct name, with a uppercase and letters', cursor_position = len(document.text)) widget = [ { 'type':'input', 'name':'nickname', 'message':'Choose a nickname :', 'qmark':'>>>', 'validate':NickNameValidator } ] try : result = prompt(widget) except ValueError : print('Pb !!!') exit() print('Your answer is') print(result["nickname"]) print(type(result["nickname"]))