def _check_url(dir_url):
    """Check dir url, will check scheme, raise error if empty scheme"""
    parsed = urlparse(dir_url)
    if not parsed.scheme:
        raise ValueError(
            'ERROR! A scheme-less directory url ({}) is no longer supported. '
            'Please prepend "file://" for local filesystem.'.format(dir_url))
Check dir url, will check scheme, raise error if empty scheme
petastorm/spark/spark_dataset_converter.py