docs: @Attribute(optional = true)
      public void set( String set )
      {
          try
          {
              this.set = Unicode.valueOf( set ).set;
          }
          catch ( IllegalArgumentException e )
          {
              if ( EOI.equals( set ) || EOF.equals( set ) )
              {
                  this.set = null;
              }
              else if ( set.length() > 2 && set.charAt( 0 ) == '[' && set.charAt( set.length() - 1 ) == ']' )
              {
                  this.set = CodePointSet.parse( set );
              }
              else
              {
                  throw new IllegalArgumentException(
                          "Invalid character set, " +
                          "should either be the name of a well known set, or a set enclosed in '[...]', " +
                          "not: " + set );
              }
          }
      }