pub fn add_claim(
  payload: Payload,
  claim: #(String, Dynamic),
) -> Payload

pub fn get_claim(
  payload: Payload,
  key: String,
  decoder: fn(Dynamic) -> Result(a, List(DecodeError)),
) -> Result(a, Error)

pub fn new() -> Payload

pub fn remove_claim(payload: Payload, key: String) -> Payload

pub fn set_claim(
  payload: Payload,
  key: String,
  value: Dynamic,
) -> Payload

pub fn to_json(payload: Payload) -> Json