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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 _make_static_dir_path(cwd, static_dir):
 """ This method returns the path to the directory where static files are to be served from. If static_dir is a relative path, then it is resolved to be relative to the current working directory. If no static directory is provided, or if the resolved directory does not exist, this method will return None :param string cwd: Current working directory relative to which we will resolve the static directory :param string static_dir: Path to the static directory :return string: Path to the static directory, if it exists. None, otherwise """

        if not static_dir:
            return None

        static_dir_path = os.path.join(cwd, static_dir)
        if os.path.exists(static_dir_path):
            LOG.info("Mounting static files from %s at /", static_dir_path)
            return static_dir_path