diff --git a/repo2docker/contentproviders/git.py b/repo2docker/contentproviders/git.py
index 43333d70..7b624a87 100644
--- a/repo2docker/contentproviders/git.py
+++ b/repo2docker/contentproviders/git.py
@@ -1,5 +1,4 @@
 import subprocess
-import sys
 
 from .base import ContentProvider, ContentProviderException
 from ..utils import execute_cmd, check_ref