code: def register(full_name, email, password, lang=None, timezone=None):
      
      response = API.register(email, full_name, password,
                              lang=lang, timezone=timezone)
      _fail_if_contains_errors(response)
      user_json = response.json()
      user = User(user_json)
      user.password = password
      return user
docs: Register a new Todoist account.
  
      :param full_name: The user's full name.
      :type full_name: str
      :param email: The user's email address.
      :type email: str
      :param password: The user's password.
      :type password: str
      :param lang: The user's language.
      :type lang: str
      :param timezone: The user's timezone.
      :type timezone: str
      :return: The Todoist user.
      :rtype: :class:`pytodoist.todoist.User`
  
      >>> from pytodoist import todoist
      >>> user = todoist.register('John Doe', 'john.doe@gmail.com', 'password')
      >>> print(user.full_name)
      John Doe