Explicity declare module's exported APIs.

BTrees/OIBTree.py

@@ -12,6 +12,12 @@
 #
 ##############################################################################
 
+__all__ = ('Bucket', 'Set', 'BTree', 'TreeSet',
+           'OIBucket', 'OISet', 'OIBTree', 'OITreeSet',
+           'union', 'intersection', 'difference',  
+           'weightedUnion', 'weightedIntersection',
+          )
+
 from zope.interface import moduleProvides
 
 from BTrees.Interfaces import IObjectIntegerBTreeModule

BTrees/OLBTree.py

@@ -12,6 +12,12 @@
 #
 ##############################################################################
 
+__all__ = ('Bucket', 'Set', 'BTree', 'TreeSet',
+           'OLBucket', 'OLSet', 'OLBTree', 'OLTreeSet',
+           'union', 'intersection', 'difference',  
+           'weightedUnion', 'weightedIntersection',
+          )
+
 from zope.interface import moduleProvides
 
 from BTrees.Interfaces import IObjectIntegerBTreeModule

BTrees/OOBTree.py

@@ -12,6 +12,11 @@
 #
 ##############################################################################
 
+__all__ = ('Bucket', 'Set', 'BTree', 'TreeSet',
+           'OOBucket', 'OOSet', 'OOBTree', 'OOTreeSet',
+           'union', 'intersection','difference',  
+          )
+
 from zope.interface import moduleProvides
 
 from BTrees.Interfaces import IObjectObjectBTreeModule