Why does it throw an error 'NoneType' object has no attribute 'startswith'?

Question

Python

I want to use code -

import aiohttp
import os
import re

uri = os.getenv("DB_URL")
if uri.startswith("postgres://"):
    uri = uri.replace("postgres://", "postgresql://", 1)
    DB_URL = 'postgresql://postgres:[email protected]:5432/parser'

And he gave me an error - Traceback (most recent call last): File "C:/Users/sinto/PycharmProjects/OLX/main.py", line 12, in import config File "C:\Users\sinto\PycharmProjects\OLX\ config.py", line 6, in if uri.startswith("postgres://"): AttributeError: 'NoneType' object has no attribute 'startswith'

Answer 1

DB_URL environment variable not set means.