参考资料：
Coursera-Sequence Models 第三周作业1

• 目标
  将日期转化为固定格式，“the 29th of August 1958", "03/30/1968", "24 JUNE 1987"——》"1958-08-29", "1968-03-30", "1987-06-24"

• attention
  动机
  If you had to translate a book's paragraph from French to English, you would not read the whole paragraph, then close the book and translate. Even during the translation process, you would read/re-read and focus on the parts of the French paragraph corresponding to the parts of the English you are writing down.

对比普通的LSTM，不同的是，将纯输入转化为context，再输入。

注意力，可以看到对应的输出只注意在最正确的部分