Heroku logs say "No module named 'urlparse'" when I use import urlparse

I'm having trouble using the following lines of code from https://devcenter.heroku.com/articles/heroku-postgresql#connecting-in-python

import os
import psycopg2
import urlparse

urlparse.uses_netloc.append("postgres")
url = urlparse.urlparse(os.environ["DATABASE_URL"])

conn = psycopg2.connect(
    database=url.path[1:],
    user=url.username,
    password=url.password,
    host=url.hostname,
    port=url.port
)

I'm using Python 3.6.2

In my Heroku logs I'm seeing:

ModuleNotFoundError: No module named 'urlparse'

Any help would be much appreciated!!