Checks if key exists in datastore. True if yes, False if no.

        :param: SHA512 hash key

        :return: whether or key not exists in datastore

def check_key(self, key: str) -> bool:
        """
        Checks if key exists in datastore. True if yes, False if no.

        :param: SHA512 hash key

        :return: whether or key not exists in datastore
        """
        keys = self.get_keys()
        return key in keys