Calendar.naive_datetime_to_iso_days
You're seeing just the callback
naive_datetime_to_iso_days
, go back to Calendar module for more information.
Link to this callback
naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond)
View SourceSpecs
naive_datetime_to_iso_days( year(), month(), day(), hour(), minute(), second(), microsecond() ) :: iso_days()
Converts the given datetime (without time zone) into the iso_days/0
format.