部署leancloud失败，提示ImportError: No module named lxml.html

部署leancloud失败，提示ImportError: No module named lxml.html，requirements.txt已包含gevent>=1.0.2,<2.0.0
lxml>3.4.4,<=3.5.1
html5lib>1.0b1,<=1.0b10
BeautifulSoup4>4.3.2,<=4.5.1
gevent-websocket>=0.9.5,<1.0.0
leancloud-sdk>=1.0.9,<=2.0.0
Werkzeug>=0.11.11,<1.0.0
Flask>=0.10.1,<1.0.0
Flask-Sockets>=0.1,<1.0
tushare>=0.5.6,<0.6.0
sqlalchemy>=1.0,<2.0
Configure>=0.3.5,<0.5

具体日志如下：
部署到：生产环境(web)
压缩项目文件 ...
生成临时文件：/var/folders/x6/p1dblf2d579b29qf8fdjm8cm0000gn/T/1480492302519.zip
开始上传项目文件 ...
2016-11-30 15:51:46 [INFO] 开始构建 20161130-155146
2016-11-30 15:51:46 [INFO] 正在下载应用代码 ...
2016-11-30 15:51:47 [INFO] 正在解压缩应用代码 ...
2016-11-30 15:51:47 [INFO] 运行环境: python (leanengine/python-base-2.7)
2016-11-30 15:51:47 [INFO] 正在下载和安装依赖项 ...
2016-11-30 15:51:54 [ERROR] 部署失败：The command '/bin/sh -c pip install -r requirements.txt -i https://pypi.tuna.tsinghua.edu.cn/simple && chown -R leanengine:leanengine .' returned a non-zero code: 1:
Requirement already satisfied (use --upgrade to upgrade): gevent<2.0.0,>=1.0.2 in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 1))
Collecting lxml<=3.5.1,>3.4.4 (from -r requirements.txt (line 2))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/8b/be/ed850baac891aca25c832fb8d7b9c0e7a5077a30e336d95ffc7d649aaa06/lxml-3.5.0.tar.gz1 (3.8MB)
Collecting html5lib<=1.0b10,>1.0b1 (from -r requirements.txt (line 3))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/2f/74/7793ca2d36f676b740efc04b7ba887c610119beb5841d1805cb3515616cb/html5lib-1.0b10-py2.py3-none-any.whl (112kB)
Collecting BeautifulSoup4<=4.5.1,>4.3.2 (from -r requirements.txt (line 4))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/dc/27/8919b7a505b00f410c1c113c6c93b3253784375797976272e4198f4e455a/beautifulsoup4-4.5.1-py2-none-any.whl (83kB)
Requirement already satisfied (use --upgrade to upgrade): gevent-websocket<1.0.0,>=0.9.5 in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 5))
Collecting leancloud-sdk<=2.0.0,>=1.0.9 (from -r requirements.txt (line 6))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/f9/8c/db2a1fbe7a00bcf20f6ec81fd275532079c19f7d5c9690ae9b2ec2fc5a90/leancloud-sdk-1.8.0.tar.gz
Collecting Werkzeug<1.0.0,>=0.11.11 (from -r requirements.txt (line 7))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/a9/5e/41f791a3f380ec50f2c4c3ef1399d9ffce6b4fe9a7f305222f014cf4fe83/Werkzeug-0.11.11-py2.py3-none-any.whl (306kB)
Collecting Flask<1.0.0,>=0.10.1 (from -r requirements.txt (line 8))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/63/2b/01f5ed23a78391f6e3e73075973da0ecb467c831376a0b09c0ec5afd7977/Flask-0.11.1-py2.py3-none-any.whl (80kB)
Collecting Flask-Sockets<1.0,>=0.1 (from -r requirements.txt (line 9))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/62/a1/2295e41c32f591093cce519282ceeb6a968945bf497faa83a124e206aa26/Flask_Sockets-0.2.1-py2.py3-none-any.whl
Collecting tushare<0.6.0,>=0.5.6 (from -r requirements.txt (line 10))
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/01/ec/294c34ab8d9ef0d316a2c4e8ff03af8d7e5f6207ab84d602e848d2c08a37/tushare-0.5.9.zip (106kB)
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "", line 1, in
File "/tmp/pip-build-PEzh_M/tushare/setup.py", line 4, in
import tushare
File "/tmp/pip-build-PEzh_M/tushare/tushare/__init__.py", line 7, in
from tushare.stock.trading import (get_hist_data, get_tick_data,
File "/tmp/pip-build-PEzh_M/tushare/tushare/stock/trading.py", line 13, in
import lxml.html
ImportError: No module named lxml.html

----------------------------------------

Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-PEzh_M/tushare/
You are using pip version 8.1.2, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

求解决方法，谢谢！