diff --git a/unit04_public_key/lab/sample_ans.md b/unit04_public_key/lab/sample_ans.md
index 95280bd..fb76543 100644
--- a/unit04_public_key/lab/sample_ans.md
+++ b/unit04_public_key/lab/sample_ans.md
@@ -571,9 +571,11 @@ Signatures match:	True
 ```python
 import rsa
 (bob_pub, bob_priv) = rsa.newkeys(512)
-print bob_pub
-print bob_priv
-ciphertext = rsa.encrypt('Here is my message', bob_pub)
+
+print (bob_pub)
+print (bob_priv)
+msg='Here is my message'
+ciphertext = rsa.encrypt(msg.encode(), bob_pub)
 message = rsa.decrypt(ciphertext, bob_priv)
 print(message.decode('utf8'))
 ```