diff --git a/binder/Pipfile.lock b/binder/Pipfile.lock
index b256af8be2..2327866915 100644
--- a/binder/Pipfile.lock
+++ b/binder/Pipfile.lock
@@ -1960,6 +1960,7 @@
                 "sha256:d9a566c40b89757c9aa8e6f032bcdb8ca8795d7c1a9762910c722b1635c9de4d",
                 "sha256:e2e20b9113cd7293f164dc46fffb13535266e713cdb87bd2d15ddb336e96cfc4"
             ],
+            "index": "pypi",
             "markers": "python_version >= '3.8'",
             "version": "==6.4.1"
         },