code: def insert_table(self, rows, cols):
          
          graphicFrame = self._new_placeholder_table(rows, cols)
          self._replace_placeholder_with(graphicFrame)
          return PlaceholderGraphicFrame(graphicFrame, self._parent)
docs: Return a |PlaceholderGraphicFrame| object containing a table of
          *rows* rows and *cols* columns. The position and width of the table
          are those of the placeholder and its height is proportional to the
          number of rows. A |PlaceholderGraphicFrame| object has all the
          properties and methods of a |GraphicFrame| shape except that the
          value of its :attr:`~._BaseSlidePlaceholder.shape_type` property is
          unconditionally `MSO_SHAPE_TYPE.PLACEHOLDER`. Note that the return
          value is not the new table but rather *contains* the new table. The
          table can be accessed using the
          :attr:`~.PlaceholderGraphicFrame.table` property of the returned
          |PlaceholderGraphicFrame| object.