PATCH doesn't allow custom data fields

[vanwars]

Hello, I'm new to the WebFlow python client, but I'm trying to programmatically update a CMS item in a collection, including some custom fields I defined. However, when I issue the following request (as suggested here: https://developers.webflow.com/data/reference/cms/collection-items/items/update-item)...

client.collections.items.update_item(
    collection_id=MY_COLLECTION_ID,
    item_id=MY_ITEM_ID,
    field_data=CollectionItemFieldData(
        custom_field_1="test"
    )
)

...I get the following error:

TypeError: ItemsClient.update_item() got an unexpected keyword argument 'field_data'

I'm using version 1.2.0. Is this a bug, or am I just misunderstanding the documentation?

UPDATE

I did get the CURL version to work, so at least that's a workaround:

curl -X PATCH https://api.webflow.com/v2/collections/MY_COLLECTION_ID/items/MY_ITEM_ID \
     -H "Authorization: Bearer MY_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
  "fieldData": {
    "custom_field_1": "test"
  }'