In [1]:
import requests

In [2]:
url = 'https://www.yahoo.co.jp/'

In [3]:
ua = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36'

In [4]:
headers = {'User-Agent': ua}

In [5]:
r_ua = requests.get(url, headers=headers)