icalendar--datetime-to-iso-date

icalendar--datetime-to-iso-date is a compiled Lisp function in `icalendar.el'.

(icalendar--datetime-to-iso-date DATETIME &optional SEPARATOR)

Convert the decoded DATETIME to ISO format.
Optional argument SEPARATOR gives the separator between month,
day, and year. If nil a blank character is used as separator.
ISO format: (year month day).