diff --git a/Lib/csv.py b/Lib/csv.py
index e0558c7..ee62abe 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -14,7 +14,8 @@
 from io import StringIO
 
 __all__ = [ "QUOTE_MINIMAL", "QUOTE_ALL", "QUOTE_NONNUMERIC", "QUOTE_NONE",
-            "Error", "Dialect", "excel", "excel_tab", "reader", "writer",
+            "Error", "Dialect", "__doc__", "excel", "excel_tab",
+            "field_size_limit", "reader", "writer",
             "register_dialect", "get_dialect", "list_dialects", "Sniffer",
             "unregister_dialect", "__version__", "DictReader", "DictWriter" ]
 
diff --git a/Lib/os.py b/Lib/os.py
index 2fdf668..19a045a 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -27,7 +27,7 @@
 _names = sys.builtin_module_names
 
 # Note:  more names are added to __all__ later.
-__all__ = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep",
+__all__ = ["altsep", "curdir", "pardir", "sep", "extsep", "pathsep", "linesep",
            "defpath", "name", "path", "devnull",
            "SEEK_SET", "SEEK_CUR", "SEEK_END"]
 
diff --git a/Lib/weakref.py b/Lib/weakref.py
index 64d962c..3301070 100644
--- a/Lib/weakref.py
+++ b/Lib/weakref.py
@@ -25,7 +25,7 @@
 ProxyTypes = (ProxyType, CallableProxyType)
 
 __all__ = ["ref", "proxy", "getweakrefcount", "getweakrefs",
-           "WeakKeyDictionary", "ReferenceType", "ProxyType",
+           "WeakKeyDictionary", "ReferenceError", "ReferenceType", "ProxyType",
            "CallableProxyType", "ProxyTypes", "WeakValueDictionary",
            "WeakSet"]