Macro find_param_method 

macro_rules! find_param_method {
    ($meth:ident, $curie:expr) => { ... };
    ($meth:ident, $curie:expr, $desc:literal) => { ... };
    ($meth:ident, $curie:expr, $conv:expr, $result:ty) => { ... };
    ($meth:ident, $curie:expr, $conv:expr, $result:ty, $desc:literal) => { ... };
}

A helper to generate methods that find a value by a CURIE