Fix ordering of imports.

dulwich/server.py

@@ -28,6 +28,7 @@ Documentation/technical directory in the cgit distribution, and in particular:
 
 import collections
 from cStringIO import StringIO
+import os
 import SocketServer
 
 from dulwich.errors import (
@@ -42,23 +43,24 @@ from dulwich.objects import (
     hex_to_sha,
     sha_to_hex,
     )
+from dulwich.pack import (
+    read_pack_header,
+    unpack_object,
+    write_pack_data,
+    )
 from dulwich.protocol import (
+    MULTI_ACK,
+    MULTI_ACK_DETAILED,
     ProtocolFile,
     ReceivableProtocol,
+    SINGLE_ACK,
     TCP_GIT_PORT,
     ZERO_SHA,
     extract_capabilities,
     extract_want_line_capabilities,
-    SINGLE_ACK,
-    MULTI_ACK,
-    MULTI_ACK_DETAILED,
     ack_type,
     )
-from dulwich.pack import (
-    read_pack_header,
-    unpack_object,
-    write_pack_data,
-    )
+
 
 class Backend(object):
     """A backend for the Git smart server implementation."""
@@ -157,7 +159,7 @@ class PackStreamVerifier(object):
     def _buf_len(self):
         buf = self._rbuf
         start = buf.tell()
-        buf.seek(0, 2)
+        buf.seek(0, os.SEEK_END)
         end = buf.tell()
         buf.seek(start)
         return end - start