diff --git a/pyproject.toml b/pyproject.toml
index f6558201..992586ee 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -143,6 +143,7 @@ line_length = 118
 [tool.mypy]
 check_untyped_defs = true
 disallow_incomplete_defs = true
+explicit_package_bases = true
 disallow_untyped_defs = true
 follow_imports = "silent"
 ignore_missing_imports = true