diff --git a/github/vscode-debug-wrapper.py b/github/vscode-debug-wrapper.py
index 6d05df8..bf992da 100755
--- a/github/vscode-debug-wrapper.py
+++ b/github/vscode-debug-wrapper.py
@@ -27,5 +27,8 @@
     # N.B. since that will also happen in pytest's doctest mode, that
     #      special case is dealt with in the parse_args function
     branch_retrieve_github_data.main()
+elif sub_command == "--doctest-modules":
+    # Another special case
+    pass
 else:
     raise SystemError(f"Unknown sub command '{sub_command}'")