functions should not modify input objects

[lenarddome]

When running metadpy.mle.metad on a pandas.DataFrame, the function modifies the original DataFrame. I believe this behaviour is unintended and might cause some issues with later data processing.

Specifically, it adds three extra columns: Subject, Within, Between.

A more appropriate way to handle this would be to create a copy of the DataFrame for internal operations of the function and leave the original object untouched.

Use the example I provided to reproduce problem: #13

[LegrandNico]

Hi @lenarddome , thank you for pointing this out. I am not maintaining this repository anymore, you can find the most recent version of the code for metadpy and the version matching the PyPi depot here. I will try to look into this issue soon.