I can use other escape characters without any problem but my atom text editor and python itself doesn't see it as an escape character but as a normal character.
print '\s', test_line
\s isn't an escape sequence in Python. \t, \n, \r etc are (see the Python lexical analysis docs) but non-special characters will not be interpreted as anything special, hence your \s appearing literally.
However, \s does means space in regular expression syntax of course...