Use %s instead of %i for string arguments to string interpolation.
Use %s instead of %i for string arguments to string interpolation.

This fixes a defect that was introduced in 2426704128f2d2c22bff476c
and tracked is tracked in issue 1678.

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