diff --git a/lib/python/pyflyby/_importstmt.py b/lib/python/pyflyby/_importstmt.py
index 0f1d2c7..26d4434 100644
--- a/lib/python/pyflyby/_importstmt.py
+++ b/lib/python/pyflyby/_importstmt.py
@@ -26,6 +26,8 @@ def read_black_config():
 
     """
     value = find_pyproject_toml('.')
+    if value is None:
+        return {}
 
     raw_config = parse_pyproject_toml(value)