Replace backticks with repr() or "%r"
From SF patch #852334.
diff --git a/Demo/tkinter/matt/animation-w-velocity-ctrl.py b/Demo/tkinter/matt/animation-w-velocity-ctrl.py
index a45f3f0..f3332f2 100644
--- a/Demo/tkinter/matt/animation-w-velocity-ctrl.py
+++ b/Demo/tkinter/matt/animation-w-velocity-ctrl.py
@@ -28,7 +28,7 @@
def moveThing(self, *args):
velocity = self.speed.get()
str = float(velocity) / 1000.0
- str = `str` + "i"
+ str = "%ri" % (str,)
self.draw.move("thing", str, str)
self.after(10, self.moveThing)