def check_hash_unchanged(hash_db, rvt_model_path, model_hash, date):
    model_info = {"<full_model_path>": str(rvt_model_path),
                  ">last_hash": model_hash,
                  ">last_hash_date": date,
                  }
    unchanged = hash_db.search((Query()["<full_model_path>"] == str(rvt_model_path)) &
                               (Query()[">last_hash"] == model_hash)
                               )
    if unchanged:
        return True
    else:
        hash_db.upsert(model_info, Query()["<full_model_path>"] == str(rvt_model_path)
                       )