def get_the_strings_that_only_contain_the_character_x(l): return [string for string in l if 'x' in string]
print get_the_strings_that_only_contain_the_character_x(['windows','mac','unix','linux','osx','vax','solaris','aix','bsd'])
ZGVmIGdldF90aGVfc3RyaW5nc190aGF0X29ubHlfY29udGFpbl90aGVfY2hhcmFjdGVyX3gobCk6IHJldHVybiBbc3RyaW5nIGZvciBzdHJpbmcgaW4gbCBpZiAneCcgaW4gc3RyaW5nXQoKcHJpbnQgZ2V0X3RoZV9zdHJpbmdzX3RoYXRfb25seV9jb250YWluX3RoZV9jaGFyYWN0ZXJfeChbJ3dpbmRvd3MnLCdtYWMnLCd1bml4JywnbGludXgnLCdvc3gnLCd2YXgnLCdzb2xhcmlzJywnYWl4JywnYnNkJ10p