Create person with new custom fields through API

Hello, i’ve created custom fields (like study_level) through api in Person, but when i try to create a new Person from the API and fill it, it say the field doesnt exist.

It appear correctly in the website form:

Thank you so much.

I solved it, when we create custom fields it returns us an id, so when we try to fill it through the API, we must call the id as “key”: