`'Sms' object has no attribute 'send_mfa'` error when sending MFA code

[IhateTrains]

For MFA I followed the example from here:

smsapi-python-client/examples/sms.py

Line 39 in 5ffbc7b

client.sms.send_mfa(phone_number='some-number', content='Your code: [%code%]', fast=0)

>>> from django.conf import settings                                                                        
>>> from smsapi.client import SmsApiPlClient                           
>>> client = SmsApiPlClient(access_token=settings.SMSAPI_ACCESS_TOKEN) 
>>> client.sms.send_mfa(phone_number="420420420", content="Twój kod weryfikacyjny: [%code%]", fast=0)       
Traceback (most recent call last):
  File "<console>", line 1, in <module>
AttributeError: 'Sms' object has no attribute 'send_mfa'
>>>

Our token is correct, sending normal SMS works just fine.
OS: Windows 11
Python version: 3.10.6

Are we doing something wrong, or is it a bug?
EDIT: Noticed this feature was added in August and hasn't been released.