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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def user_config_dir(appname=None, appauthor=None, version=None, roaming=False):
 r"""Return full path to the user-specific config dir for this application. "appname" is the name of application. If None, just the system directory is returned. "appauthor" (only used on Windows) is the name of the appauthor or distributing body for this application. Typically it is the owning company name. This falls back to appname. You may pass False to disable it. "version" is an optional version path element to append to the path. You might want to use this if you want multiple versions of your app to be able to run independently. If used, this would typically be "<major>.<minor>". Only applied when appname is present. "roaming" (boolean, default False) can be set True to use the Windows roaming appdata directory. That means that for users on a Windows network setup for roaming profiles, this user data will be sync'd on login. See <http://technet.microsoft.com/en-us/library/cc766489(WS.10).aspx> for a discussion of issues. Typical user config directories are: Mac OS X: same as user_data_dir Unix: ~/.config/<AppName> # or in $XDG_CONFIG_HOME, if defined Win *: same as user_data_dir For Unix, we follow the XDG spec and support $XDG_CONFIG_HOME. That means, by default "~/.config/<AppName>". """

    if system in ["win32", "darwin"]:
        path = user_data_dir(appname, appauthor, None, roaming)
    else:
        path = os.getenv('XDG_CONFIG_HOME', os.path.expanduser("~/.config"))
        if appname:
            path = os.path.join(path, appname)
    if appname and version:
        path = os.path.join(path, version)
    return path