### What problem does this PR solve?
Add get_txt function to reduce duplicate code
### Type of change
- [x] Refactoring
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Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
### What problem does this PR solve?
- Update readme
- Add license
### Type of change
- [x] Documentation Update
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Signed-off-by: Jin Hai <haijin.chn@gmail.com>