Collecting zope.preference==4.0.0
  1 location(s) to search for versions of zope.preference:
  * https://pypi.python.org/simple/zope-preference/
  Getting page https://pypi.python.org/simple/zope-preference/
  Analyzing links from page https://pypi.python.org/simple/zope-preference/
    Found link https://pypi.python.org/packages/3c/34/6b5580d2dfa7f186f39c3db0902e5480fcf7703582affda7486f87354e18/zope.preference-4.0.0.tar.gz#md5=fb61d39a154f16e3ace8525e82016d78 (from https://pypi.python.org/simple/zope-preference/), version: 4.0.0
    Found link https://pypi.python.org/packages/43/ff/71dcd8078f0d8954228cd6941814d6e7d8daf3b69671bb7774eacfcf04a9/zope.preference-4.0.0a1.zip#md5=6b7d5fd1c4399290211e65cf26172a61 (from https://pypi.python.org/simple/zope-preference/), version: 4.0.0a1
    Found link https://pypi.python.org/packages/5c/23/3cd5b7334ce1d992d7ebb5e5f6bbbf410ecedf757c51b1949c92d6721a7c/zope.preference-3.8.0.tar.gz#md5=bb8b1c9f65387a51be429407528cc453 (from https://pypi.python.org/simple/zope-preference/), version: 3.8.0
    Found link https://pypi.python.org/packages/9f/a6/8d5c32dc07cd843ff30da8e174e9e6546210fba266fa26871ba42759cc27/zope.preference-4.0.0-py2.py3-none-any.whl#md5=901a19913721828f2393ecc03b47f12d (from https://pypi.python.org/simple/zope-preference/), version: 4.0.0
  Using version 4.0.0 (newest of versions: 4.0.0)
  Downloading zope.preference-4.0.0-py2.py3-none-any.whl
  Downloading from URL https://pypi.python.org/packages/9f/a6/8d5c32dc07cd843ff30da8e174e9e6546210fba266fa26871ba42759cc27/zope.preference-4.0.0-py2.py3-none-any.whl#md5=901a19913721828f2393ecc03b47f12d (from https://pypi.python.org/simple/zope-preference/)
  Saved /tmp/tmppn0n2k0f/zope.preference-4.0.0-py2.py3-none-any.whl
Skipping zope.preference, due to already being wheel.
Cleaning up...
  Removing source in /tmp/pip-build-cf20ghz4/zope.preference