Exception: Add exception with message box for not implement method.

src/Model/Geometry/PointXY.py

@@ -31,6 +31,9 @@ class PointAC(Point):
     def c(self, value):
         self._c = float(value)
 
+    def dist(self, p2):
+        return PointAC.distance(self, p2)
+
     @staticmethod
     def distance(p1, p2):
         """Euclidean distance between p1 and p2.