code: def auto_shape_type(self):
          
          prstGeom = self._pic.spPr.prstGeom
          if prstGeom is None:  # ---generally means cropped with freeform---
              return None
          return prstGeom.prst
docs: Member of MSO_SHAPE indicating masking shape.
  
          A picture can be masked by any of the so-called "auto-shapes"
          available in PowerPoint, such as an ellipse or triangle. When
          a picture is masked by a shape, the shape assumes the same dimensions
          as the picture and the portion of the picture outside the shape
          boundaries does not appear. Note the default value for
          a newly-inserted picture is `MSO_AUTO_SHAPE_TYPE.RECTANGLE`, which
          performs no cropping because the extents of the rectangle exactly
          correspond to the extents of the picture.
  
          The available shapes correspond to the members of
          :ref:`MsoAutoShapeType`.
  
          The return value can also be |None|, indicating the picture either
          has no geometry (not expected) or has custom geometry, like
          a freeform shape. A picture with no geometry will have no visible
          representation on the slide, although it can be selected. This is
          because without geometry, there is no "inside-the-shape" for it to
          appear in.