code: public final boolean openAt(@NotNull final HourRange range) {
          Contract.requireArgNotNull("range", range);
          ensureSingleDayOnly("this", this);
  
          final BitSet original = range.toMinutes();
          final BitSet anded = range.toMinutes();
          anded.and(this.toMinutes());
  
          return anded.equals(original);
  
      }
docs: Determines if this instance if "open" at the given time range.<br>
  <br>
  It is only allowed to call this method if the hour ranges represents only one day. This means a value like '18:00-03:00' will lead to
  an error. To avoid this, call the {@link #normalize()} function before this one and pass the result per day as an argument to this
  method.
  
  @param range
  Time range to verify.
  
  @return {@literal true} if open else {@literal false} if not open.