[enh] don't put a space at the end of a trailing tuple
[enh] same for other data structures
[fix] don't put a space after an empty comment
[mod] be cautious, it seems that the comment stuff happens in very special case here
[enh] not so good case for magic print_function not imported from future
[enh] replace tabs by space
[enh] correctly reindent a file, god that was not trivial