diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 000000000..108d9976e
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,12 @@
+sudo: false
+language: python
+python:
+  - "3.5"
+  # More versions later.
+
+install:
+  - pip install git+git://github.com/JukkaL/mypy
+
+script:
+  - mypy stdlib/3/
+  # That doesn't test everything, but it's a start.
diff --git a/stdlib/3/traceback.pyi b/stdlib/3/traceback.pyi
index d0cc403a4..21c256496 100644
--- a/stdlib/3/traceback.pyi
+++ b/stdlib/3/traceback.pyi
@@ -1,5 +1,6 @@
 # Stubs for traceback
 
+from types import TracebackType
 import typing
 
 # TODO signatures