this python file is used for removing "\n" or "\s"{2:} when you copy something from file.pdf.
for example,if you are reading a paper in English and you want to copy some contents in pdf and translate them by google-translate, but the result of translation will be confused because there are many "\n" in your clipboard, then you can use it to tackle it. just run it in the background
based on blog https://blog.csdn.net/liukcqu/article/details/7890724 I try to copy the code and use it, but it doesn't work, so I rewrite it by python re.