1 files changed, 19 insertions, 0 deletions
diff --git a/challenge-308/roger-bell-west/python/ch-2.py b/challenge-308/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..5ebb9fe738
--- /dev/null
+++ b/challenge-308/roger-bell-west/python/ch-2.py
@@ -0,0 +1,19 @@
+#! /usr/bin/python3
+
+def decodexor(a, init):
+  out = [init]
+  for v in a:
+    out.append(out[-1] ^ v)
+  return out
+
+import unittest
+
+class TestDecodexor(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(decodexor([1, 2, 3], 1), [1, 0, 2, 1], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(decodexor([6, 2, 7, 3], 4), [4, 2, 0, 7, 4], 'example 2')
+
+unittest.main()