Can prefix method return the postions of the result ?

[bojone]

I find prefix method in all of your trie modules does not return the postions of the result. For example, datrie module:

trie.prefix_items(u'foobarbaz') [(u'foo', 5), (u'foobar', 10)]

How can I get the start postion or end postion of the result "foo" and "foobar"?