diff --git a/py_gen/templates/_ofclass.py b/py_gen/templates/_ofclass.py
index c84ceea..f902ae8 100644
--- a/py_gen/templates/_ofclass.py
+++ b/py_gen/templates/_ofclass.py
@@ -28,7 +28,7 @@
         return ''.join(packed)
 
     @staticmethod
-    def unpack(buf):
+    def unpack(reader):
         obj = ${ofclass.pyname}()
 :: include("_unpack.py", ofclass=ofclass)
         return obj
diff --git a/py_gen/templates/_unpack.py b/py_gen/templates/_unpack.py
index c3d3fd3..b762a9c 100644
--- a/py_gen/templates/_unpack.py
+++ b/py_gen/templates/_unpack.py
@@ -28,10 +28,6 @@
 :: # TODO coalesce format strings
 :: from loxi_ir import *
 :: from py_gen.oftype import gen_unpack_expr
-        if type(buf) == loxi.generic_util.OFReader:
-            reader = buf
-        else:
-            reader = loxi.generic_util.OFReader(buf)
 :: field_length_members = {}
 :: for m in ofclass.members:
 ::     if type(m) == OFPadMember: