diff --git a/cython_extensions/bootstrap.pyx b/cython_extensions/bootstrap.pyx
index 6bf3486..b147832 100644
--- a/cython_extensions/bootstrap.pyx
+++ b/cython_extensions/bootstrap.pyx
@@ -1,5 +1,7 @@
 import importlib
 import importlib.abc
+import importlib.util
+import importlib.machinery
 import sys