https://stackoverflow.com/questions/22748295/python-decision-tree-classifier-batch-prob-classify-function
http://www.ithao123.cn/content-236308.html
http://blog.csdn.net/yan456jie/article/details/52242790
http://f.dataguru.cn/thread-713072-1-1.html
http://blog.csdn.net/chenglansky/article/details/31371033
斯坦福分类器中文实现 http://www.52nlp.cn/python%E8%87%AA%E7%84%B6%E8%AF%AD%E8%A8%80%E5%A4%84%E7%90%86%E5%AE%9E%E8%B7%B5-%E5%9C%A8nltk%E4%B8%AD%E4%BD%BF%E7%94%A8%E6%96%AF%E5%9D%A6%E7%A6%8F%E4%B8%AD%E6%96%87%E5%88%86%E8%AF%8D%E5%99%A8