Function verify_with_keys 

fn verify_with_keys<'a>(
    keys: impl IntoIterator<Item = &'a str>,
    alg: &str,
    signing_input: &[u8],
    signature: &[u8],
) -> Result<&'a str, ApiError>

Verifies signing_input’s signature against every multibase key in keys on the curve alg names, answering the key that verified it.