from pathlib import Path


def is_dir_gzipped(directory: str) -> bool:
    """
    Check if the all the files in directory have a '.gz' extension
    """
    files = Path(directory).glob("**")
    if not files:
        return False
    files = filter(lambda x: x.is_file(), files)
    for f in files:
        if f.suffix != ".gz":
            return False
    return True