def charts
      charts = @anchors.select { |a| a.object.is_a?(GraphicFrame) }
      charts.map { |a| a.object.chart }
    end
def charts
      charts = @anchors.select { |a| a.object.is_a?(GraphicFrame) }
      charts.map { |a| a.object.chart }
    end
An array of charts that are associated with this drawing's anchors
 @return [Array]