Update documentation on interface as well.
diff --git a/cryptography/hazmat/primitives/interfaces.py b/cryptography/hazmat/primitives/interfaces.py
index c6377df..4143d64 100644
--- a/cryptography/hazmat/primitives/interfaces.py
+++ b/cryptography/hazmat/primitives/interfaces.py
@@ -164,7 +164,8 @@
         """
 
     @abc.abstractmethod
-    def verify(self, sig):
+    def verify(self, signature):
         """
-        compare digest to sig and raise exception if not equal.
+        Compare hash digest to signature and raises InvalidSignature
+        they are not equal.
         """