IsLeapYear returns true if `year` is a leap year, and false otherwise.

NewDateComponents creates a new DateComponents using the year, month and day in `t`.

NewTimeComponents creates a TimeComponents struct given `d`, representing hours.

ResolveTime creates a time.Time struct given `year`, `month` and `day`.

ResolveTimeByDateComponents converts `c` to the corresponding time.Time value.

RoundToNearestMinute rounds to the closest minute for `d`.