def distinct_values driver = nil
      @distinct_values ||= values || @filters.values.inject({}){|memo, filter| memo[filter.name] = filter.label; memo }
    end
def distinct_values driver = nil
      @distinct_values ||= values || @filters.values.inject({}){|memo, filter| memo[filter.name] = filter.label; memo }
    end
returns map { :name => label }