diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index 846d56b..f1a1a3e 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -315,8 +315,8 @@
     except IOError:
         return None
     db = MimeTypes()
-    db.readfp(f)
-    return db.types_map
+    db.readfp(f, True)
+    return db.types_map[True]
 
 
 suffix_map = {