def is_uri(self, filename):
    proto = filename.split('://', 1)[0]
    return (proto in ('http', 'https', 'ftp', 'smb', 'S3'))
def is_uri(self, filename):
    proto = filename.split('://', 1)[0]
    return (proto in ('http', 'https', 'ftp', 'smb', 'S3'))