使用BeautifulSoup从html解析表并将其另存为csv时出现问题

import requests
import csv
import requests
from bs4 import BeautifulSoup

r = requests.get('https://pqt.cbp.gov/report/YYZ_1/12-01-2017')
soup = BeautifulSoup(r)
table = soup.find('table', attrs={ "class" : "table-horizontal-line"})
headers = [header.text for header in table.find_all('th')]
rows = []
for row in table.find_all('tr'):
    rows.append([val.text.encode('utf8') for val in row.find_all('td')])

with open('output_file.csv', 'wb') as f:
    writer = csv.writer(f)
    writer.writerow(headers)
    writer.writerows(row for row in rows if row)

我正在尝试解析此特定网页中的所有表数据：https : //pqt.cbp.gov/report/YYZ_1/12-01-2017

我在一行中出错soup = BeautifulSoup(r)。我得到一个错误TypeError: object of type 'Response' has no len()。我也不确定我的逻辑是否正确。请帮我粘贴表格数据。