def delete(self, shape=None, part=None, point=None):
        """Deletes the specified part of any shape by specifying a shape
        number, part number, or point number."""
        # shape, part, point
        if shape and part and point:
            del self._shapes[shape][part][point]
        # shape, part
        elif shape and part and not point:
            del self._shapes[shape][part]
        # shape
        elif shape and not part and not point:
            del self._shapes[shape]
        # point
        elif not shape and not part and point:
            for s in self._shapes:
                if s.shapeType == 1:
                    del self._shapes[point]
                else:
                    for part in s.parts:
                        del s[part][point]
        # part, point
        elif not shape and part and point:
            for s in self._shapes:
                del s[part][point]
        # part
        elif not shape and part and not point:
            for s in self._shapes:
                del s[part]
Deletes the specified part of any shape by specifying a shape
        number, part number, or point number.