Google 的官方案例模型：
https://github.com/tensorflow/models/tree/master/official/r1/wide_deep
requirement: https://github.com/tensorflow/models/tree/master/official
feature columns 详细说明：
https://tensorflow.google.cn/tutorials/structured_data/feature_columns?hl=zh-cn
feature columns 案例说明：
http://xudongyang.coding.me/tensorflow-feature-columns/
Dataset 详细说明：
https://tensorflow.google.cn/versions/r1.14/api_docs/python/tf/data/Dataset