diff --git a/src/mega/mega.py b/src/mega/mega.py
index 38df858..9b7b401 100644
--- a/src/mega/mega.py
+++ b/src/mega/mega.py
@@ -59,8 +59,9 @@ class Mega(object):
                 a32_to_base64(encrypt_key(master_key, password_key)),
                 'ts':
                 base64_url_encode(
-                    a32_to_str(session_self_challenge) +
-                    a32_to_str(encrypt_key(session_self_challenge, master_key))
+                    a32_to_str(session_self_challenge) + a32_to_str(
+                        encrypt_key(session_self_challenge, master_key)
+                    )
                 )
             }
         )