capybara/virtualenv/lib/python2.7/site.py
def addusersitepackages(known_paths):
    """Add a per user site-package to sys.path

    Each user has its own python directory with site-packages in the
    home directory.

    USER_BASE is the root directory for all Python versions

    USER_SITE is the user specific site-packages directory

    USER_SITE/.. can be used for data.
    """
    global USER_BASE, USER_SITE, ENABLE_USER_SITE
    env_base = os.environ.get("PYTHONUSERBASE", None)

    def joinuser(*args):
        return os.path.expanduser(os.path.join(*args))

    #if sys.platform in ('os2emx', 'riscos'):
    #    # Don't know what to put here
    #    USER_BASE = ''
    #    USER_SITE = ''
    if os.name == "nt":
        base = os.environ.get("APPDATA") or "~"
        if env_base:
            USER_BASE = env_base
        else:
            USER_BASE = joinuser(base, "Python")
        USER_SITE = os.path.join(USER_BASE,
                                 "Python" + sys.version[0] + sys.version[2],
                                 "site-packages")
    else:
        if env_base:
            USER_BASE = env_base
        else:
            USER_BASE = joinuser("~", ".local")
        USER_SITE = os.path.join(USER_BASE, "lib",
                                 "python" + sys.version[:3],
                                 "site-packages")

    if ENABLE_USER_SITE and os.path.isdir(USER_SITE):
        addsitedir(USER_SITE, known_paths)
    if ENABLE_USER_SITE:
        for dist_libdir in ("lib", "local/lib"):
            user_site = os.path.join(USER_BASE, dist_libdir,
                                     "python" + sys.version[:3],
                                     "dist-packages")
            if os.path.isdir(user_site):
                addsitedir(user_site, known_paths)
    return known_paths
def addusersitepackages(known_paths):
    """Add a per user site-package to sys.path

    Each user has its own python directory with site-packages in the
    home directory.

    USER_BASE is the root directory for all Python versions

    USER_SITE is the user specific site-packages directory

    USER_SITE/.. can be used for data.
    """
    global USER_BASE, USER_SITE, ENABLE_USER_SITE
    env_base = os.environ.get("PYTHONUSERBASE", None)

    def joinuser(*args):
        return os.path.expanduser(os.path.join(*args))

    #if sys.platform in ('os2emx', 'riscos'):
    #    # Don't know what to put here
    #    USER_BASE = ''
    #    USER_SITE = ''
    if os.name == "nt":
        base = os.environ.get("APPDATA") or "~"
        if env_base:
            USER_BASE = env_base
        else:
            USER_BASE = joinuser(base, "Python")
        USER_SITE = os.path.join(USER_BASE,
                                 "Python" + sys.version[0] + sys.version[2],
                                 "site-packages")
    else:
        if env_base:
            USER_BASE = env_base
        else:
            USER_BASE = joinuser("~", ".local")
        USER_SITE = os.path.join(USER_BASE, "lib",
                                 "python" + sys.version[:3],
                                 "site-packages")

    if ENABLE_USER_SITE and os.path.isdir(USER_SITE):
        addsitedir(USER_SITE, known_paths)
    if ENABLE_USER_SITE:
        for dist_libdir in ("lib", "local/lib"):
            user_site = os.path.join(USER_BASE, dist_libdir,
                                     "python" + sys.version[:3],
                                     "dist-packages")
            if os.path.isdir(user_site):
                addsitedir(user_site, known_paths)
    return known_paths
Add a per user site-package to sys.path

    Each user has its own python directory with site-packages in the
    home directory.

    USER_BASE is the root directory for all Python versions

    USER_SITE is the user specific site-packages directory

    USER_SITE/.. can be used for data.