fun compareTo(other: Calendar): Int
Returns -1, 0, 1 if the instance is less than, equal to, or greater than specified Calendar instance, respectively.
fun compareTo(other: Long): Int
Returns -1, 0, 1 if the instance is less than, equal to, or greater than specified number of milliseconds from epoch, respectively.
open fun compareTo(other: DateTime): Int
Returns -1, 0, 1 if the instance is less than, equal to, or greater than other instance, respectively.