pub fn parse(selector: String, json: serde_json::Value) -> Result<String, RatError> {
let parts = selector.split(".");
let mut selected = &json;
for p in parts {
selected = &selected[p];
}
match selected.as_str() {
Some(v) => Ok(v.to_string()),
None => Err(RatError::InvalidSelector(selector)),
}
}