diff --git a/setup.py b/setup.py
index ae821ac..3c84091 100644
--- a/setup.py
+++ b/setup.py
@@ -28,7 +28,9 @@ install_requires = [
     'six>=1.5',
     'contextlib2; python_version=="2.7"',
     'mock; python_version=="2.7"',
-    'yarl; python_version>="3.4"',
+    'yarl; python_version>"3.4"',
+    'yarl<1.0.0; python_version=="3.4"',
+    'multidict<4.0.0,>=2.0; python_version=="3.4"'
 ]
 
 excluded_packages = ["tests*"]
diff --git a/vcr/serializers/jsonserializer.py b/vcr/serializers/jsonserializer.py
index 3378c27..000c894 100644
--- a/vcr/serializers/jsonserializer.py
+++ b/vcr/serializers/jsonserializer.py
@@ -25,5 +25,5 @@ def serialize(cassette_dict):
             original.end,
             original.args[-1] + error_message
         )
-    except TypeError as original:  # py3
+    except TypeError:  # py3
         raise TypeError(error_message)