1 files changed, 4 insertions, 0 deletions
diff --git a/wsgitools/applications.py b/wsgitools/applications.py
index 4ddf7ea..5ef2e8a 100644
--- a/wsgitools/applications.py
+++ b/wsgitools/applications.py
@@ -8,6 +8,9 @@ class StaticContent:
         content contains the data to be delivered to the client. It is either a
                 string or some kind of iterable yielding strings.
         """
+        assert isinstance(status, str)
+        assert isinstance(headers, list)
+        assert hasattr(content, "__iter__")
         self.status = status
         self.headers = headers
         length = -1
@@ -23,6 +26,7 @@ class StaticContent:
                 headers.append(("Content-length", str(length)))
     def __call__(self, environ, start_response):
         """wsgi interface"""
+        assert isinstance(environ, dict)
         start_response(self.status, self.headers)
         if environ["REQUEST_METHOD"].upper() == "HEAD":
             return []