diff --git a/src/_secureaccesstokenauthorizer/tests/strategies.py b/src/_secureaccesstokenauthorizer/tests/strategies.py
index 7ecf774bc0fd063e184964efd5a7011e2cefcdd8..898989e87320976dc7c2518094d97a55beab8220 100644
--- a/src/_secureaccesstokenauthorizer/tests/strategies.py
+++ b/src/_secureaccesstokenauthorizer/tests/strategies.py
@@ -143,7 +143,7 @@ def shares():
         sharenums(),
         sizes()
     ).map(
-        lambda (num, size): bytes_for_share(num, size),
+        lambda num_and_size: bytes_for_share(*num_and_size),
     )