expr:         `cidr("192.168.0.0/24").containsCIDR(cidr("192.168.0.0/25"))`,
			expectResult: trueVal,
		},
		{
			name:         "does not contain IP ipv4 (CIDR)",
			expr:         `cidr("192.168.0.0/24").containsCIDR(cidr("192.168.0.0/23"))`,
			expectResult: falseVal,
		},
		{
			name:         "contains CIDR ipv4 (string)",
			expr:         `cidr("192.168.0.0/24").containsCIDR("192.168.0.0/25")`,
			expectResult: trueVal,

// cidr('192.168.0.0/24').containsIP('192.168.1.1') // returns false
// cidr('192.168.0.0/16').containsCIDR(cidr('192.168.10.0/24')) // returns true
// cidr('192.168.1.0/24').containsCIDR(cidr('192.168.2.0/24')) // returns false
// cidr('192.168.0.0/16').containsCIDR('192.168.10.0/24') // returns true
// cidr('192.168.1.0/24').containsCIDR('192.168.2.0/24') // returns false
// cidr('192.168.0.1/24').ip() // returns ipAddr('192.168.0.1')

	ipv4Cases := append(cases, []testCase{
		{
			ops: []string{".containsCIDR(cidr('192.0.0.0/30'))"},
			expectEsimatedCost: func(c checker.CostEstimate) checker.CostEstimate {
				return checker.CostEstimate{Min: c.Min + 5, Max: c.Max + 9}
			},
			expectRuntimeCost: func(c uint64) uint64 { return c + 5 },
		},
		{
			ops: []string{".containsCIDR(cidr('192.168.0.0/16'))"},

		// Kubernetes <1.30>:
		"ip", "family", "isUnspecified", "isLoopback", "isLinkLocalMulticast", "isLinkLocalUnicast", "isGlobalUnicast", "ip.isCanonical", "isIP", "cidr", "containsIP", "containsCIDR", "masked", "prefixLength", "isCIDR", "string",
		// Kubernetes <1.??>:
	)

	// TODO: test celgo function lists

	unexpected := functionNames.Difference(knownFunctions)

				cost += uint64(math.Ceil(float64(otherSize) * common.StringTraversalCostFactor))

			}

			return &cost
		}
	case "containsCIDR":
		if len(args) >= 2 {
			cidrSize := actualSize(args[0])
			otherSize := actualSize(args[1])

			// This is the base cost of comparing two byte lists.

				`ip("192.168.0.1").isGlobalUnicast()`,
				`type(ip("192.168.0.1")) == net.IP`,
				`cidr("192.168.0.0/24").containsIP(ip("192.168.0.1"))`,
				`cidr("192.168.0.0/24").containsCIDR("192.168.0.0/25")`,
				`cidr("2001:db8::/32").containsCIDR(cidr("2001:db8::/33"))`,
				`type(cidr("2001:db8::/32").ip()) == net.IP`,
				`cidr('192.168.0.0/24') == cidr('192.168.0.0/24').masked()`,
				`cidr('192.168.0.0/16').prefixLength() == 16`,