response = requests.get(URL, params=params,
      headers=headers, timeout=10)
print 'self.encoding',response.encoding
output:
self.encoding ISO-8859-1

In [14]: a = '约' #utf-8编码
In [15]: a
Out[15]: '\xe7\xba\xa6'
In [22]: b=a.decode('ISO-8859-1')#response.text 认为响应内容是ISO-8859-1编码,将其decode为Unicode
In [23]: b
Out[23]: u'\xe7\xba\xa6'
In [26]: c=b.encode('utf8')#如果我们没有注意ISO-8859-1,直接以utf8对其进行编码
In [27]: c
Out[27]: '\xc3\xa7\xc2\xba\xc2\xa6'#那么encode得到的utf-8,在显示器上显示的就是乱码,因为'约'的utf-8编码是'\xe7\xba\xa6'

In [13]: a = '约' #Unicode
In [14]: type(a)
Out[14]: str
In [15]: b=a.encode('utf8')
In [16]: b
Out[16]: b'\xe7\xba\xa6'
In [17]: type(b)
Out[17]: bytes
In [27]: b'\xe7\xba\xa623,000'.decode('ISO-8859-1')
Out[27]: '约23,000'
In [28]: type(b'\xe7\xba\xa623,000'.decode('ISO-8859-1'))
Out[28]: str
In [29]: b'\xe7\xba\xa623,000'.decode('utf8')
Out[29]: '约23,000'

import requests
headers = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) '
   'AppleWebKit/537.36 (KHTML, like Gecko) '
   'Chrome/56.0.2924.87 Safari/537.36'}
proxies = {'http': 'socks5://127.0.0.1:1080','https':'socks5://127.0.0.1:1080'}
url = 'https://www.facebook.com'
response = requests.get(url, proxies=proxies)
print(response.content)