def formatter_for(klass) #:nodoc:
      while klass != nil do
        formatter = @class_formatters[klass]
        return formatter if formatter
        klass = klass.superclass
      end
      @_default_formatter
    end
def formatter_for(klass) #:nodoc:
      while klass != nil do
        formatter = @class_formatters[klass]
        return formatter if formatter
        klass = klass.superclass
      end
      @_default_formatter
    end
Find the formatter for a class by looking it up using the class hierarchy.