code: def font(self):
          
          txPr = self._get_or_add_txPr()
          text_frame = TextFrame(txPr, self)
          paragraph = text_frame.paragraphs[0]
          return paragraph.font
docs: The |Font| object providing text formatting for this data label.
  
          This font object is used to customize the appearance of automatically
          inserted text, such as the data point value. The font applies to the
          entire data label. More granular control of the appearance of custom
          data label text is controlled by a font object on runs in the text
          frame.