@classmethod
def get_version(cls, settings, path):
    """Generate the version string to be used in static URLs.
        ``settings`` is the `Application.settings` dictionary and ``path``
        is the relative location of the requested asset on the filesystem.
        The returned value should be a string, or ``None`` if no version
        could be determined.
        .. versionchanged:: 3.1
           This method was previously recommended for subclasses to override;
           `get_content_version` is now preferred as it allows the base
           class to handle caching of the result.
        """
    abs_path = cls.get_absolute_path(settings['static_path'], path)
    return cls._get_cached_version(abs_path)
