Chris Jerdonek added the comment: Thanks for the report. Minor clarification for future reference. Subsequent lines should begin with "..." (when doctest-style is used): >>> def breadth_first_search(unsearched): ... node = unsearched.popleft() etc. ---------- nosy: +chris.jerdonek _______________________________________ Python tracker <report at bugs.python.org> <http://bugs.python.org/issue16020> _______________________________________