curl --request POST \
  --url https://api.prime.coinbase.com/v1/portfolios/{portfolio_id}/onchain_address_group \
  --header 'Content-Type: application/json' \
  --data '
{
  "address_group": {
    "id": "<string>",
    "name": "<string>",
    "network_type": "NETWORK_TYPE_UNSPECIFIED",
    "addresses": [
      {
        "name": "<string>",
        "address": "<string>",
        "chain_ids": [
          "<string>"
        ]
      }
    ],
    "added_at": "2023-11-07T05:31:56Z"
  }
}
'

{
  "num_approvals_remaining": 123,
  "activity_id": "<string>"
}