code: public final String getStartFormattedMedium() {
          Granularity startGran = this.interval.getStartGranularity();
          return formatStart(startGran != null ? startGran.getMediumFormat()
                  : null);
      }
docs: Returns the earliest valid time of this proposition as a medium-length
  string.
  
  @return a <code>String</code>.