Need OIC date format for days-from-duration and syntax of command

Summary: Need syntax and date format for command used in logger and/or assignment for the purpose of getting the date 90 days before current date.

Content (please ensure you mask any confidential information):

Below is what I've tried in a logger and some in an assignment. I get a value does not match required type error.

fn:current-dateTime()-fn:days-from-duration('P90D')

fn:current-date()-fn:days-from-duration('P90D')

fn:current-dateTime()-fn:days-from-duration("P90D")

fn:current-date()-fn:days-from-duration("P90D")

I could really use some direction. Thanks!

Version (include the version you are using, if applicable): OIC 3

Code Snippet (add any code snippets that support your topic, if applicable):