code: public Calendar computeSunriseCalendar(Zenith solarZenith, Calendar date) {
          return getLocalTimeAsCalendar(computeSolarEventTime(solarZenith, date, true), date);
      }
docs: Computes the sunrise time for the given zenith at the given date.
  
  @param solarZenith
  <code>Zenith</code> enum corresponding to the type of sunrise to compute.
  @param date
  <code>Calendar</code> object representing the date to compute the sunrise for.
  @return the sunrise time as a calendar or null for no sunrise