curl --location '/trainings/custom-fields' \
--header 'api-key: <api-key>'{
"status": 200,
"custom_fields": [
{
"id": 0,
"updated_at": "2019-08-24T14:15:22.123Z",
"custom_field_type": "string",
"field_name_attribute": "string",
"custom_field_name": "string",
"display_name_label": "string"
}
]
}