Collecting bison==0.0.1
  1 location(s) to search for versions of bison:
  * https://pypi.python.org/simple/bison/
  Getting page https://pypi.python.org/simple/bison/
  Analyzing links from page https://pypi.python.org/simple/bison/
    Found link https://pypi.python.org/packages/4c/2b/be4601218f6c5e968da2580c0ece23fead89781ccaec938017e11699e19b/bison-0.0.1.tar.gz#md5=ce4bc1e3c06889101566dcf3620d27a0 (from https://pypi.python.org/simple/bison/) (requires-python:>=3.4), version: 0.0.1
    Found link https://pypi.python.org/packages/d0/59/1665577e705feaa2f0135e0de779cbb0f75b546ca8ddbfbc4960431dc0a0/bison-0.0.1-py2.py3-none-any.whl#md5=7c77e696bd15019fae2a6438f77919f6 (from https://pypi.python.org/simple/bison/) (requires-python:>=3.4), version: 0.0.1
  Using version 0.0.1 (newest of versions: 0.0.1)
  Downloading bison-0.0.1-py2.py3-none-any.whl
  Downloading from URL https://pypi.python.org/packages/d0/59/1665577e705feaa2f0135e0de779cbb0f75b546ca8ddbfbc4960431dc0a0/bison-0.0.1-py2.py3-none-any.whl#md5=7c77e696bd15019fae2a6438f77919f6 (from https://pypi.python.org/simple/bison/) (requires-python:>=3.4)
  Saved /tmp/tmpnmheu4zz/bison-0.0.1-py2.py3-none-any.whl
Skipping bison, due to already being wheel.
Cleaning up...
  Removing source in /tmp/pip-build-0bk8xexm/bison