df=True not working #38

I was trying to use openaq.OpenAQ.countries() method with df=True as a parameter so that I will get an output as a Pandas DataFrame but when I ran the code, I am just receiving output in the dictionary format,
Output :

Code :

import openaq
api = openaq.OpenAQ()
status, res = api.countries(df=True)
print(res)

OS : Windows 10
Python version : 3.7.8
openaq version = 1.1.0