#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum Error {
#[error(
"invalid custom chart kind {0:?}: use 1-64 of a-z, 0-9, -; start with a letter; do not use a built-in name"
)]
InvalidKind(String),
#[error("chart data does not serialize to JSON: {0}")]
Json(#[from] serde_json::Error),
}