Handle non-iterable arguments reasonable
diff --git a/cryptography/fernet.py b/cryptography/fernet.py
index 6bc401d..4f98fee 100644
--- a/cryptography/fernet.py
+++ b/cryptography/fernet.py
@@ -131,6 +131,7 @@
class MultiFernet(object):
def __init__(self, fernets):
+ fernets = list(fernets)
if not fernets:
raise ValueError(
"MultiFernet requires at least one Fernet instance"
diff --git a/tests/test_fernet.py b/tests/test_fernet.py
index 91af32a..58f89cb 100644
--- a/tests/test_fernet.py
+++ b/tests/test_fernet.py
@@ -146,3 +146,7 @@
def test_no_fernets(self, backend):
with pytest.raises(ValueError):
MultiFernet([])
+
+ def test_non_iterable_argument(self, backend):
+ with pytest.raises(TypeError):
+ MultiFernet(None)