Not all exceptions have an "args" attribute of length at least one.
Not all exceptions have an "args" attribute of length at least one.

This fixes a defect introduced (or at least greatly widened in
scope) in revision a55cde7d9e8526a8af0c51.

rhyolight/nupic.son,rhyolight/nupic.son,rhyolight/nupic.son