Update custom fields via API
I've been struggling to update custom fields using the API (via your Python package).
The most similar problem I can find reported is https://support.insight.ly/hc/en-us/community/posts/222741027-Update-CustomFields-api
I have successfully read my custom field data, and updated standard fields, but when I try to update custom fields I get an HTTP 400 error.
It seems to be making 2 PUT requests, the first of which succeeds and the second of which fails.