diff --git a/hgdemandimport/__init__.py b/hgdemandimport/__init__.py
--- a/hgdemandimport/__init__.py
+++ b/hgdemandimport/__init__.py
@@ -46,6 +46,7 @@
     # setuptools' pkg_resources.py expects "from __main__ import x" to
     # raise ImportError if x not defined
     '__main__',
+    '_ast', # https://bugs.python.org/issue41631
     '_ssl',  # conditional imports in the stdlib, issue1964
     '_sre',  # issue4920
     'rfc822',