In order to edit files generated by the Pylons framework it is necessary to configure your text editor with the following rules:
insert space characters whenever the tab key is pressed.
set the number of spaces to 4 whenever the tab key is pressed.
I am using the Vim editor and here is the content of my .vimrc file: syntax on set ts=4 set sw=4 set expandtab set nu set hlsearch set ai set nocompatible set showmatch