diff --git a/mitogen/master.py b/mitogen/master.py
index 7a9f1dd9..be417a5f 100644
--- a/mitogen/master.py
+++ b/mitogen/master.py
@@ -145,24 +145,24 @@ LOAD_CONST = dis.opname.index('LOAD_CONST')
 IMPORT_NAME = dis.opname.index('IMPORT_NAME')
 
 
+def _getarg(c):
+    if c < dis.HAVE_ARGUMENT:
+        return nextb()
+    return nextb() | (nextb() << 8)
+
+
 if sys.version_info < (3, 0):
     def iter_opcodes(co):
         # Yield `(op, oparg)` tuples from the code object `co`.
         ordit = imap(ord, co.co_code)
         nextb = ordit.next
-        return ((c, (None
-                     if c < dis.HAVE_ARGUMENT else
-                     (nextb() | (nextb() << 8))))
-                    for c in ordit)
+        return ((c, _getarg(c)) for c in ordit)
 elif sys.version_info < (3, 6):
     def iter_opcodes(co):
         # Yield `(op, oparg)` tuples from the code object `co`.
         ordit = iter(co.co_code)
         nextb = ordit.__next__
-        return ((c, (None
-                     if c < dis.HAVE_ARGUMENT else
-                     (nextb() | (nextb() << 8))))
-                    for c in ordit)
+        return ((c, _getarg(c)) for c in ordit)
 else:
     def iter_opcodes(co):
         # Yield `(op, oparg)` tuples from the code object `co`.