diff --git a/diskimage_builder/elements/pypi/pre-install.d/04-configure-pypi-mirror b/diskimage_builder/elements/pypi/pre-install.d/04-configure-pypi-mirror
index 9ad74c45..335f3d58 100755
--- a/diskimage_builder/elements/pypi/pre-install.d/04-configure-pypi-mirror
+++ b/diskimage_builder/elements/pypi/pre-install.d/04-configure-pypi-mirror
@@ -57,8 +57,10 @@ def main():
         output.write('trusted-host =  %s\n' % (urlparse(indices[0]).hostname,))
         if retries is not None:
             output.write('retries = %s\n' % retries)
-        for index in indices[1:]:
-            output.write('extra-index-url = %s\n' % (index,))
+        if len(indices) > 1:
+            output.write('extra-index-url =\n')
+            for index in indices[1:]:
+                output.write('    %s\n' % (index,))
     with open(home + '/.pydistutils.cfg', 'wt') as output:
         output.write('[easy_install]\n')
         output.write('index_url = %s\n' % (easy_index,))