def unicode_test(seg_instance, seg_str):
            seg_gen_str = str(seg_instance)

            self.assertEqual(len(seg_gen_str), 240)
            self.assertEqual(len(seg_str), 240)
            self.assertEqual(seg_gen_str, seg_str)
def get_leafs(self):
		if self.lchild == None and self.rchild == None:
			return [self.leaf]
		else:
			return self.lchild.get_leafs()+self.rchild.get_leafs()