About the secluded example

[Leon K. W. Kwok]

Dear developers,

My name is Leon and I am trying to use your secluded example(example_secluded.ipynb) to compute some results for my project.
However, when I try to run it, there is a error message staying that TabError: inconsistent use of tabs and spaces in indentation in your propa.py. As suggested by the statement itself, the problem could be the misuse of tab and space for indentation. And this happens in some lines of code.
Right now I am trying to fix it one by one until I can import propa probably.
You may read https://stackoverflow.com/questions/5685406/inconsistent-use-of-tabs-and-spaces-in-indentation for more detailed explanation.

Best regards,
Leon

[Qinrui Liu]

The format should be fixed now.