pep8 & pep263

http://www.python.org/dev/peps/pep-0008/#tabs-or-spaces

> Spaces are the preferred indentation method.

http://www.python.org/dev/peps/pep-0263/

> More precisely, the first or second line must match the regular
    expression "coding[:=]\s*([-\w.]+)". 

It makes no sense if the coding is not in the first or second line.