The sep='\t' can be use in many forms, for example if you want to read tab separated value: Example: I have a dataset tsv = tab separated value NOT comma separated value df = pd.read_csv('gapminder.tsv'). when you try to read this, it will give you an error because you have tab separated value not csv. so you need to give read csv a different parameter called sep='\t'.
Now you can read: df = pd.read_csv('gapminder.tsv, sep='\t'), with this you can read the it.