docs: public Object convert( String value, TypeLiteral<?> toType )
      {
          int separator = value.indexOf( '_' );
          if ( separator != -1 )
          {
              String language = value.substring( 0, separator );
              String country = value.substring( separator + 1 );
              return new Locale( language, country );
          }
          return new Locale( value );
      }