How to use XLSX workbook with Python

Flat files (CSV) are generally used with Python as a common practice, but some specific application require using of XLSX workbook with interrelated data instead of flat CSV files. But using this XLSX if not initialized properly tends to create unexpected errors and does not allow linkage of python code with XLSX file. There are many open source packages available to be used with python but only some are generating results as expected. Can anyone help on this?