diff --git a/pyproject.toml b/pyproject.toml
index ae91d28..3e82fbb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,5 +35,8 @@ Repository = "https://github.com/Vedantgitbot/booth"
 [tool.setuptools.packages.find]
 where = ["src"]
 
+[tool.setuptools.package-data]
+booth = ["py.typed"]
+
 [tool.pytest.ini_options]
 testpaths = ["tests"]
\ No newline at end of file
diff --git a/src/booth/core.py b/src/booth/core.py
index c2b8e73..27b5d76 100644
--- a/src/booth/core.py
+++ b/src/booth/core.py
@@ -464,7 +464,7 @@ def _evaluate(
     if attempt.parse_ok and not attempt.passed_validation:
         return None
 
-    if attempt.parse_ok and attempt.confidence >= threshold:
+    if attempt.parse_ok and attempt.confidence is not None and attempt.confidence >= threshold:
         status = ACCEPTED if attempt_index == 0 else REPAIRED
         return BoothResult(
             answer=attempt.answer,
diff --git a/src/booth/py.typed b/src/booth/py.typed
new file mode 100644
index 0000000..e69de29