diff --git a/IPython/nbconvert/transformers/svg2pdf.py b/IPython/nbconvert/transformers/svg2pdf.py
index 15a37a0..d02f414 100644
--- a/IPython/nbconvert/transformers/svg2pdf.py
+++ b/IPython/nbconvert/transformers/svg2pdf.py
@@ -14,6 +14,9 @@ one format to another.
 #-----------------------------------------------------------------------------
 
 import os
+import sys
+import subprocess
+
 from IPython.utils.tempdir import TemporaryDirectory
 
 from .convertfigures import ConvertFiguresTransformer