def METHOD_NAME(
    event: EventBase, hash_algorithm: Hasher = hashlib.sha256
) -> Tuple[str, bytes]:
    """Computes the event reference hash. This is the hash of the redacted
    event.
    Args:
        event
        hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
            to hash the event
    Returns:
        A tuple of the name of hash and the hash as raw bytes.
    """
    tmp_event = prune_event(event)
    event_dict = tmp_event.get_pdu_json()
    event_dict.pop("signatures", None)
    event_dict.pop("age_ts", None)
    event_dict.pop("unsigned", None)
    event_json_bytes = encode_canonical_json(event_dict)
    hashed = hash_algorithm(event_json_bytes)
    return hashed.name, hashed.digest()