def is_valid_cidr_netmask(cidr_netmask: str) -> bool:
    """
    This function will check that the netmask given in
    parameter is a correct mask for IPv4 IP address.
    Using to verify a netmask in CIDR (/24) format.

    :param cidr_netmask: Netmask to check
    :return bool: True if the netmask is valid
    """

    return str(cidr_netmask).isdigit() and \
        int(cidr_netmask) >= 0 and \
        int(cidr_netmask) <= 32