make a directory to store all caches

        Returns:
        ---------
            cache path

def cache_path(self):
        """
        make a directory to store all caches

        Returns:
        ---------
            cache path
        """
        cache_path = os.path.join(os.path.dirname(__file__), '..', 'cache')
        if not os.path.exists(cache_path):
            os.mkdir(cache_path)
        return cache_path