how to extract multiple columns stored using indentation in Excel using python

I have an excel which is structured like this: The different levels of ledgers are all coded in the first column itself using indentation.

I want to extract the different levels and flatten them like this - I have used openpyxl to read and write by cells, columns or rows. But I am not sure how I can approach the different levels of data all stored in one column using indentation. Any pointers on how I can approach the problem using python would be appreciated.