fairseq-preprocess, Why are the number of rows in src and trg different?
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## Details
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After I used subword_nmt for bpe, when using preprocess, I found that the number of rows read src and trg are not equal, but I checked the data after bpe, the number of rows of src and trg are equal, although trg has dozens of Blank lines, the results here show that the gap between the number of lines in src and trg is much larger than the number of blank lines.
![image](https://user-images.githubusercontent.com/35246891/80357931-431ecb00-88ae-11ea-8cce-5fd4cb9b75f9.png)
![image](https://user-images.githubusercontent.com/35246891/80358019-60ec3000-88ae-11ea-9f0f-5ae6181292c3.png)

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<|||||>have you fixed this problem?