add Line.setPt()

Line.py

@@ -24,3 +24,8 @@ class Line(Shape):
             return (self.vars[0], self.vars[1])
         elif ptNum == 1:
             return (self.vars[2], self.vars[3])
+
+    def setPt(self, ptNum, pt):
+        base = ptNum * 2
+        self.vars[base + 0] = pt[0]
+        self.vars[base + 1] = pt[1]