Python 3 won't compile with mixed indentation so by recommending a mixture you're picking a fight you cannot win and still have python programmers along with you.
As long as you always “indent” with tabs and only use spaces after, you’re good, I believe. That is, if you want to align something, you just first indent to the level of the previous line with tabs and then you can use spaces for alignment within that indentation level. What you can’t do is, for example, have a space and then a tab.
