curl --request POST \
--url https://api.international.coinbase.com/api/v1/portfolios/margin \
--header 'CB-ACCESS-KEY: <api-key>' \
--header 'CB-ACCESS-PASSPHRASE: <api-key>' \
--header 'CB-ACCESS-SIGN: <api-key>' \
--header 'CB-ACCESS-TIMESTAMP: <api-key>' \
--header 'Content-Type: application/json' \
--data '{
"portfolio_id": "<string>",
"margin_override": "<string>"
}'