MacOS Version10.11.6
安装python scrapy时报错如下：
distutils.errors.DistutilsError: Could not find suitable distribution for Requirement.parse('incremental>=16.10.1')
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Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/jt/3kzp3p6n4fj6771x6bkhf6cm0000gn/T/pip-install-bKSoUE/Twisted/
解决办法：Command Line------
sudo pip install incremental==17.5.0
pip install scrapy