That warnings appears with python3.6: ``` past/types/oldstr.py:33: DeprecationWarning: invalid escape sequence \d ``` Apparently the broken code is inside docstring example but is enough to pollute any test executions on a library using python-future. An easy solution is to replace the example with another escape which is still valid, like a ``\n`` instead of ``\\d``. Also a release would be needed.