Fix typo in tuple error message

cassandra/cqltypes.py

@@ -807,7 +807,7 @@ class TupleType(_ParameterizedType):
     @classmethod
     def serialize_safe(cls, val, protocol_version):
         if len(val) > len(cls.subtypes):
-            raise ValueError("Expected %d items in a tuple, but only got %d: %s" %
+            raise ValueError("Expected %d items in a tuple, but got %d: %s" %
                              (len(cls.subtypes), len(val), val))
 
         proto_version = max(3, protocol_version)