fix import

ox/api.py

@@ -6,6 +6,7 @@ import gzip
 import os
 import shutil
 import sys
+import time
 
 from six.moves import http_cookiejar as cookielib
 from six import BytesIO, PY2
@@ -160,7 +161,6 @@ class API(object):
             f = open(filename, 'rb')
             fsize = os.stat(filename).st_size
             done = 0
-            start = time.mktime(time.localtime())
             if 'offset' in data and data['offset'] < fsize:
                 done = data['offset']
                 f.seek(done)