s.send("CAP REQ :twitch.tv/membership")
s.send("CAP REQ :twitch.tv/commands")
s.send("CAP REQ :twitch.tv/tags")
should be
s.send("CAP REQ :twitch.tv/membership\r\n")
s.send("CAP REQ :twitch.tv/commands\r\n")
s.send("CAP REQ :twitch.tv/tags\r\n")
or
s.send("CAP REQ :twitch.tv/membership twitch.tv/commands twitch.tv/tags\r\n")
You were not terminating your lines with a carriage return