http://tehbemfqolualhxwkyimu3bdob5s4hkrfuwbwxzbblncjy2j2owgolqd.onion/documentation.html
This function should return either: None , a string representing the command's standard output, a 2-tuple of strings, representing stdout and stderr, or a 3-tuple containing stdout, stderr, and an integer representing the command's return code.