SOLVED. I had to POST the following to set_miner_conf.cgi:
data = {
"pools": [
{
"url": "antpool.com:3333",
"user": "antminer1,
"pass": ""
},
{
"url": "antpool.com:3333",
"user": "antminer1",
"pass": ""
},
{
"url": "antpool.com:3333",
"user": "antminer1",
"pass": ""
}
]
}