diff --git a/bootstrapvz/plugins/puppet/tasks.py b/bootstrapvz/plugins/puppet/tasks.py
index aedb312..2607a76 100644
--- a/bootstrapvz/plugins/puppet/tasks.py
+++ b/bootstrapvz/plugins/puppet/tasks.py
@@ -5,7 +5,6 @@ from bootstrapvz.common.tasks import apt
 from bootstrapvz.common.exceptions import TaskError
 from bootstrapvz.common.releases import jessie, wheezy, stretch
 from bootstrapvz.common.tools import sed_i, log_check_call, rel_path
-from __builtin__ import str
 
 
 ASSETS_DIR_STRETCH = rel_path(__file__, 'assets/gpg-keyrings-PC1/stretch')
diff --git a/bootstrapvz/remote/build_servers/callback.py b/bootstrapvz/remote/build_servers/callback.py
index 40223ba..395cebc 100644
--- a/bootstrapvz/remote/build_servers/callback.py
+++ b/bootstrapvz/remote/build_servers/callback.py
@@ -22,7 +22,7 @@ class CallbackServer(object):
         self.thread.start()
         return self
 
-    def __exit__(self, type, value, traceback):
+    def __exit__(self, exception_type, exception_value, traceback):
         log.debug('Shutting down callback server')
         self.daemon.shutdown()
         self.thread.join()