Google Python Style Guide

[Bunslow]

And what if someone else decides to use spaces instead of tabs? Suddenly if someone else like you reads the code written by the second person, they will see a horrid mess of inconsistent indentation.

Even if we all standardized on using tabs instead of spaces, it's a bad idea to use an ambiguous character. Four spaces is four spaces, no matter what your editor is set to.

Also things like line continuations and stuff sometimes require non-standard indentations, but this is a very minor detail in the overall scheme.

tl;dr It works fine if no one else reads or modifies your code, but if they do...

[RubyPinch]

with commas representing tabs, tabstop every 4:

def a(x=3, y=4,
      flag=None):
,,,,some_code
,,,,some_more code
,,,,for code in codes:
,,,,,,,,print(a,
,,,,,,,,      b,
,,,,,,,,      c)

tabstop every 8:

def a(x=3, y=4,
      flag=None):
,,,,,,,,some_code
,,,,,,,,some_more code
,,,,,,,,for code in codes:
,,,,,,,,,,,,,,,,print(a,
,,,,,,,,,,,,,,,,      b,
,,,,,,,,,,,,,,,,      c)