import hashlib


def blake2b(filename: str) -> str:
    """Get blake2b digest for a file.

    Args:
        filename (str): The file to get a blake2b digest of.

    Returns:
        str: A blake2b hexdigest.
    """
    with open(filename, "rb") as f:
        file_hash = hashlib.blake2b()
        while chunk := f.read(8192):
            file_hash.update(chunk)
    return file_hash.hexdigest()