curl --request POST \
  --url https://api.opx.co/partners/v1/conventions \
  --header 'Content-Type: application/json' \
  --data '
{
  "contract_template_id": 123,
  "installer_siret": "<string>",
  "installer_contact_email": "jsmith@example.com"
}
'

{
  "data": {
    "id": 123,
    "contract_template_id": 123,
    "reference": "<string>",
    "rai_name": "<string>",
    "status": 123,
    "installer_name": "<string>",
    "signed_date": "<string>",
    "start_date": "<string>",
    "end_date": "<string>",
    "incentive_type": 123,
    "classic_volume": "<string>",
    "precarity_volume": "<string>",
    "is_active": true,
    "is_expired": "<string>"
  }
}