diff --git a/benchmark/addressbook.capnp.bytes.py b/benchmark/addressbook.capnp.bytes.py
deleted file mode 100644
index 2f126e3..0000000
--- a/benchmark/addressbook.capnp.bytes.py
+++ /dev/null
@@ -1,54 +0,0 @@
-from __future__ import print_function
-import os
-import capnp
-
-this_dir = os.path.dirname(__file__)
-addressbook = capnp.load(os.path.join(this_dir, 'addressbook.capnp'))
-
-print = lambda *x: x
-
-
-def writeAddressBook(f):
-    addressBook = addressbook.AddressBook.new_message()
-    people = addressBook.init('people', 2)
-
-    alice = people[0]
-    alice.id = 123
-    alice.name = 'Alice'
-    alice.email = 'alice@example.com'
-    alicePhones = alice.init('phones', 1)
-    alicePhones[0].number = "555-1212"
-    alicePhones[0].type = 'mobile'
-
-    bob = people[1]
-    bob.id = 456
-    bob.name = 'Bob'
-    bob.email = 'bob@example.com'
-    bobPhones = bob.init('phones', 2)
-    bobPhones[0].number = "555-4567"
-    bobPhones[0].type = 'home'
-    bobPhones[1].number = "555-7654"
-    bobPhones[1].type = 'work'
-
-    msg_bytes = addressBook.to_bytes()
-    f.write(msg_bytes)
-
-def printAddressBook(msg_bytes):
-    addressBook = addressbook.AddressBook.from_bytes(msg_bytes)
-
-    for person in addressBook.people:
-        print(person.name, ':', person.email)
-        for phone in person.phones:
-            print(phone.type, ':', phone.number)
-        print()
-
-
-if __name__ == '__main__':
-    for i in range(10000):
-        f = open('example', 'w')
-        writeAddressBook(f)
-
-        f = open('example', 'r')
-        printAddressBook(f.read())
-
-os.remove('example')
diff --git a/benchmark/addressbook.capnp.orphan.py b/benchmark/addressbook.capnp.orphan.py
index ac71abd..cc2c8f5 100644
--- a/benchmark/addressbook.capnp.orphan.py
+++ b/benchmark/addressbook.capnp.orphan.py
@@ -8,10 +8,9 @@ addressbook = capnp.load(os.path.join(this_dir, 'addressbook.capnp'))
 print = lambda *x: x
 
 
-def writeAddressBook(fd):
-    message = capnp.MallocMessageBuilder()
-    addressBook = message.initRoot(addressbook.AddressBook)
-    people = addressBook.initResizableList('people')
+def writeAddressBook():
+    addressBook = addressbook.AddressBook.new_message()
+    people = addressBook.init_resizable_list('people')
 
     alice = people.add()
     alice.id = 123
@@ -32,13 +31,11 @@ def writeAddressBook(fd):
     bobPhones[1].type = 'work'
 
     people.finish()
+    msg_bytes = addressBook.to_bytes()
+    return msg_bytes
 
-    capnp.writePackedMessageToFd(fd, message)
-
-
-def printAddressBook(fd):
-    message = capnp.PackedFdMessageReader(f.fileno())
-    addressBook = message.getRoot(addressbook.AddressBook)
+def printAddressBook(msg_bytes):
+    addressBook = addressbook.AddressBook.from_bytes(msg_bytes)
 
     for person in addressBook.people:
         print(person.name, ':', person.email)
@@ -49,10 +46,7 @@ def printAddressBook(fd):
 
 if __name__ == '__main__':
     for i in range(10000):
-        f = open('example', 'w')
-        writeAddressBook(f.fileno())
+        msg_bytes = writeAddressBook()
 
-        f = open('example', 'r')
-        printAddressBook(f.fileno())
+        printAddressBook(msg_bytes)
 
-os.remove('example')
diff --git a/benchmark/addressbook.capnp.py b/benchmark/addressbook.capnp.py
index 8d0cdf3..b21975a 100644
--- a/benchmark/addressbook.capnp.py
+++ b/benchmark/addressbook.capnp.py
@@ -8,7 +8,7 @@ addressbook = capnp.load(os.path.join(this_dir, 'addressbook.capnp'))
 print = lambda *x: x
 
 
-def writeAddressBook(f):
+def writeAddressBook():
     addressBook = addressbook.AddressBook.new_message()
     people = addressBook.init('people', 2)
 
@@ -30,11 +30,11 @@ def writeAddressBook(f):
     bobPhones[1].number = "555-7654"
     bobPhones[1].type = 'work'
 
-    addressBook.write(f)
+    msg_bytes = addressBook.to_bytes()
+    return msg_bytes
 
-
-def printAddressBook(f):
-    addressBook = addressbook.AddressBook.read(f)
+def printAddressBook(msg_bytes):
+    addressBook = addressbook.AddressBook.from_bytes(msg_bytes)
 
     for person in addressBook.people:
         print(person.name, ':', person.email)
@@ -45,10 +45,7 @@ def printAddressBook(f):
 
 if __name__ == '__main__':
     for i in range(10000):
-        f = open('example', 'w')
-        writeAddressBook(f)
+        msg_bytes = writeAddressBook()
 
-        f = open('example', 'r')
-        printAddressBook(f)
+        printAddressBook(msg_bytes)
 
-os.remove('example')
diff --git a/benchmark/addressbook.proto.py b/benchmark/addressbook.proto.py
index 7311a99..517b44c 100644
--- a/benchmark/addressbook.proto.py
+++ b/benchmark/addressbook.proto.py
@@ -5,7 +5,7 @@ import os
 print = lambda *x: x
 
 
-def writeAddressBook(fd):
+def writeAddressBook():
     addressBook = addressbook.AddressBook()
 
     alice = addressBook.person.add()
@@ -27,12 +27,12 @@ def writeAddressBook(fd):
     bobPhones[1].type = addressbook.Person.WORK
 
     message_string = addressBook.SerializeToString()
-    fd.write(message_string)
+    return message_string
 
 
-def printAddressBook(fd):
+def printAddressBook(message_string):
     addressBook = addressbook.AddressBook()
-    addressBook.ParseFromString(fd.read())
+    addressBook.ParseFromString(message_string)
 
     for person in addressBook.person:
         print(person.name, ':', person.email)
@@ -43,10 +43,7 @@ def printAddressBook(fd):
 
 if __name__ == '__main__':
     for i in range(10000):
-        f = open('example', 'w')
-        writeAddressBook(f)
+        message_string = writeAddressBook()
 
-        f = open('example', 'r')
-        printAddressBook(f)
+        printAddressBook(message_string)
 
-os.remove('example')