def keyPressEvent(self, ev):
ch = ev.text()
if ch == 'j':
self.tree = self.nextTree()
elif ch == 'k':
self.tree = self.prevTree()
elif ch == 'h':
self.layout = self.prevLayout()
elif ch == 'l':
self.layout = self.nextLayout()
elif ch == 'r':
trees[self.treeIndex] = BinaryTree.random()
self.tree = self.curTree()
else:
super(Widget, self).keyPressEvent(ev)
self.init()
