源代码：

import requests
from bs4 import BeautifulSoup
try:
	kv = {'user_Agent':'Mozilla/5.0'}
	demo = requests.get('http://www.ugirl.com',headers = kv)
	demo.raise_for_status()
	soup = BeautifulSoup(demo,'html.parser')		
	print(soup.prettify())		#以html文本格式打印
except:
	print('解析错误')

遇到错误：

错误原因：
因为这里的demo是requests对象，无法用BeautifulSoup解析，可以在demo后面加上content。

import requests
from bs4 import BeautifulSoup
try:
	kv = {'user_Agent':'Mozilla/5.0'}
	demo = requests.get('http://www.ugirl.com',headers = kv)
	demo.raise_for_status()
	soup = BeautifulSoup(demo.content,'html.parser')		
	print(soup.prettify())		#以html文本格式打印
except:
	print('解析错误')

正确运行：