code: public static final Function<Collection<? extends Date>, Period> dateFieldCollectionToPeriod(final Chronology chronology) {
  		return FnPeriod.dateFieldCollectionToPeriod(chronology);
  	}
docs: <p>
  The function receives a {@link Collection} of two {@link Date} elements used as the start and end of the
  {@link Period} it creates. The {@link Period} will be created using the
  specified {@link Chronology}
  </p>
  
  @param chronology {@link Chronology} to be used
  
  @return the {@link Period} created from the input and arguments