How to list free IPs in subnet using oci or any other method?

Summary

In a situation of subnet that includes big number of VM machines , how to figure out the available private IPs before creating new VM?

Content

the below is listing only reserved or allocated , I need the opposite , this just an example from small subnet

oci network private-ip list --subnet-id ocid1.subnet.oc1.eu-frankfurt-1.aaaaaaaassbeypdf66zeghoumsq4rgumdnah7v3choc6qbdiys7tbsha75yq
{
  "data": [
    {
      "availability-domain": "ZNfx:EU-FRANKFURT-1-AD-3",
      "compartment-id": "ocid1.compartment.oc1..aaaa,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,",
      "defined-tags": {
        "Oracle-Tags": {
          "CreatedBy": ",,,,,,,,,,,,,,,,,,,",
          "CreatedOn": "2020-07-27T12:32:55.135Z"
        }
      },
      "display-name": "instance-20200727-1532",
      "freeform-tags": {},
      "hostname-label": "instance-20200727-1532",
      "id": "ocid1.privateip.oc1.eu-frankfurt-1.abtheljtkhyp7cwg3lzfwkkrnvlrru4uciovgawioxx5wqscbi2ss5dhxqfq",
      "ip-address": "10.0.1.2",