def _windows_system_appdata():
    """
    Return the path to the Windows Common App Data folder.
    On Windows 7, for example, this is C:\\ProgramData

    :return: String reprsentation the path to the Windows Common
             App Data folder
    """
    # Could also use os.environ['ALLUSERSPROFILE'] - maybe?
    csidl_common_appdata = 35
    sh_get_folder_path = windll.shell32.SHGetFolderPathW
    sh_get_folder_path.argtypes = [wintypes.HWND,
                                   ctypes.c_int,
                                   wintypes.HANDLE,
                                   wintypes.DWORD,
                                   wintypes.LPCWSTR]
    path_buf = ctypes.create_unicode_buffer(wintypes.MAX_PATH)
    result = sh_get_folder_path(0, csidl_common_appdata, 0, 0, path_buf)
    return str(path_buf.value)