I started off with `, "--prefix=#{prefix}"` but this happens:
```
$ brew -v install cookiecutter
Homebrew 0.9.5
Warning: A newer Command Line Tools release is available
The standalone package can be obtained from
https://developer.apple.com/downloads/,
or it can be installed via Xcode's preferences.
==> Downloading https://pypi.python.org/packages/source/c/cookiecutter/cookiecutter-0.7.0.tar.gz
Already downloaded: /Library/Caches/Homebrew/cookiecutter-0.7.0.tar.gz
tar xf /Library/Caches/Homebrew/cookiecutter-0.7.0.tar.gz
brew: PYTHONPATH=/usr/local/Cellar/cookiecutter/0.7.0/lib/python2.7/site-packages:/usr/local/Cellar/cookiecutter/0.7.0/libexec/lib/python2.7/site-packages
==> /usr/local/opt/python/bin/python2 setup.py install --prefix=/usr/local/Cellar/cookiecutter/0.7.0
running install
running bdist_egg
running egg_info
writing requirements to cookiecutter.egg-info/requires.txt
writing cookiecutter.egg-info/PKG-INFO
writing top-level names to cookiecutter.egg-info/top_level.txt
writing dependency_links to cookiecutter.egg-info/dependency_links.txt
writing entry points to cookiecutter.egg-info/entry_points.txt
reading manifest file 'cookiecutter.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'cookiecutter.egg-info/SOURCES.txt'
installing library code to build/bdist.macosx-10.8-x86_64/egg
running install_lib
running build_py
creating build
creating build/lib
creating build/lib/cookiecutter
copying cookiecutter/__init__.py -> build/lib/cookiecutter
copying cookiecutter/config.py -> build/lib/cookiecutter
copying cookiecutter/exceptions.py -> build/lib/cookiecutter
copying cookiecutter/find.py -> build/lib/cookiecutter
copying cookiecutter/generate.py -> build/lib/cookiecutter
copying cookiecutter/hooks.py -> build/lib/cookiecutter
copying cookiecutter/main.py -> build/lib/cookiecutter
copying cookiecutter/prompt.py -> build/lib/cookiecutter
copying cookiecutter/utils.py -> build/lib/cookiecutter
copying cookiecutter/vcs.py -> build/lib/cookiecutter
creating build/bdist.macosx-10.8-x86_64
creating build/bdist.macosx-10.8-x86_64/egg
creating build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/__init__.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/config.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/exceptions.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/find.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/generate.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/hooks.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/main.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/prompt.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/utils.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
copying build/lib/cookiecutter/vcs.py -> build/bdist.macosx-10.8-x86_64/egg/cookiecutter
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/__init__.py to __init__.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/config.py to config.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/exceptions.py to exceptions.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/find.py to find.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/generate.py to generate.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/hooks.py to hooks.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/main.py to main.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/prompt.py to prompt.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/utils.py to utils.pyc
byte-compiling build/bdist.macosx-10.8-x86_64/egg/cookiecutter/vcs.py to vcs.pyc
creating build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/PKG-INFO -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/SOURCES.txt -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/dependency_links.txt -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/entry_points.txt -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/not-zip-safe -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/requires.txt -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
copying cookiecutter.egg-info/top_level.txt -> build/bdist.macosx-10.8-x86_64/egg/EGG-INFO
creating dist
creating 'dist/cookiecutter-0.7.0-py2.7.egg' and adding 'build/bdist.macosx-10.8-x86_64/egg' to it
removing 'build/bdist.macosx-10.8-x86_64/egg' (and everything under it)
Creating /usr/local/Cellar/cookiecutter/0.7.0/lib/python2.7/site-packages/site.py
Processing cookiecutter-0.7.0-py2.7.egg
creating /usr/local/Cellar/cookiecutter/0.7.0/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg
Extracting cookiecutter-0.7.0-py2.7.egg to /usr/local/Cellar/cookiecutter/0.7.0/lib/python2.7/site-packages
Adding cookiecutter 0.7.0 to easy-install.pth file
Installing cookiecutter script to /usr/local/Cellar/cookiecutter/0.7.0/bin

Installed /usr/local/Cellar/cookiecutter/0.7.0/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg
Processing dependencies for cookiecutter==0.7.0
Searching for PyYAML==3.10
Best match: PyYAML 3.10
Adding PyYAML 3.10 to easy-install.pth file

Using /usr/local/lib/python2.7/site-packages
Searching for Jinja2==2.7.1
Best match: Jinja2 2.7.1
Adding Jinja2 2.7.1 to easy-install.pth file

Using /usr/local/lib/python2.7/site-packages
Searching for binaryornot==0.2.0
Best match: binaryornot 0.2.0
Processing binaryornot-0.2.0-py2.7.egg
Adding binaryornot 0.2.0 to easy-install.pth file

Using /usr/local/lib/python2.7/site-packages/binaryornot-0.2.0-py2.7.egg
Searching for MarkupSafe==0.18
Best match: MarkupSafe 0.18
Adding MarkupSafe 0.18 to easy-install.pth file

Using /usr/local/lib/python2.7/site-packages
Finished processing dependencies for cookiecutter==0.7.0
==> Cleaning
rmdir: /usr/local/Cellar/cookiecutter/0.7.0/libexec/lib/python2.7 (empty)
rmdir: /usr/local/Cellar/cookiecutter/0.7.0/libexec/lib (empty)
rmdir: /usr/local/Cellar/cookiecutter/0.7.0/libexec (empty)
==> Finishing up
ln -s ../Cellar/cookiecutter/0.7.0/bin/cookiecutter cookiecutter
Warning: Could not link cookiecutter. Unlinking...
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
You can try again using `brew link cookiecutter'

Possible conflicting files are:
/usr/local/bin/cookiecutter
/usr/local/lib/python2.7/site-packages/site.py
/usr/local/lib/python2.7/site-packages/easy-install.pth
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/top_level.txt
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/SOURCES.txt
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/requires.txt
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/PKG-INFO
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/not-zip-safe
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/entry_points.txt
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/EGG-INFO/dependency_links.txt
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/vcs.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/utils.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/prompt.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/main.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/hooks.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/generate.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/find.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/exceptions.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/config.py
/usr/local/lib/python2.7/site-packages/cookiecutter-0.7.0-py2.7.egg/cookiecutter/__init__.py
==> Summary
/usr/local/Cellar/cookiecutter/0.7.0: 33 files, 160K, built in 2 seconds
```