Not work as "More folders containing files to be copied as-is into the output"

[lengyueyang]

I have two folders under posts, and I want to copy all these folders when nikola build, I add config in conf.py,

FILES_FOLDERS = {'posts/ltxpng': 'posts/ltxpng'}
FILES_FOLDERS = {'posts/MSimg': 'posts/MSimg'}

When nikola build, only the last worked, I don't konw why?

[lengyueyang]

FILES_FOLDERS = {'posts/ltxpng': 'posts/ltxpng', 'posts/MSimg': 'posts/MSimg', 'posts/file':'posts/file'}