CiscoDNA IPAM create pool broken

[techpriest002]

Attempting to create pools with:

POST /ipam/pool

results in operations that do not seem to properly understand block hierarchy, refusing to create valid IP4 Blocks in the platform and instead erroneously report conflicts.

Steps to reproduce

1. Create Gateway installation running 21.8.1
2. Create a configuration "testconfig" in BAM platform and define a top-level block of 172.16.0.0/16.
3. Within the 172.16.0.0/16 block, create block 172.16.0.0/20 in the BAM UI.
4. Using the IPAM driver endpoint, attempt to create another block (pool):

{
    "view": "testconfig",
    "poolName": "DNACPool",
    "poolCidr": "172.16.16.0/20",
    "DHCPServerip": [],
    "DNSServerip": [],
    "ClientOptions": []
}

Current Behavior

The IPAM driver returns an HTTP error code 400 with the following payload:

Server raised fault: "Block conflicts with another in the address space. Adding: 172.16.16.0/20 Existing: 172.16.0.0/16"

This can be easily be proven to be an incorrect error message as the 172.16.16.0/20 block can be created in the BAM user interface without any issues.

Expected Behavior

The IPAM driver should be consistent with the user interface when creating IP4 Blocks. It should not incorrectly report a conflict with the containing IP4Block. For example, there is nothing wrong with creating 172.16.16.0/20 within 172.160.0.0/16.